The committee also granted amnesty to Wilson Mogotwo Sebiloane, a member of an elite Umkhonto weSizwe unit, convicted of attempted murder for injuring two policemen during a shoot-out in Johannesburg in 1991.
The committee's decisions were announced in a statement issued on Friday.
Amnesty was refused for two members of self-defence units in the Western Cape, Ndithini Thyido and Zwelitsha Mkuhlwa, who killed a fellow SDU member and a child in Khayelitsha.
Steyn, formerly a warrant officer with the Empangeni murder and robbery squad, was convicted of murder and attempted murder in the Pietermartizburg Supreme Court in December 1992, and sentenced to 18 years' imprisonment.
He shot Michael Mthethwa and Simon Msweni after they had been injured in a fight with security forces in the Sokhulu Reserve in the KwaMbonambi district of KwaZulu-Natal in August 1992.
Three policemen were killed in the clash. The two men were being taken to hospital in a police van when Steyn shot each of them twice.
The committee found Steyn had made full disclosure of his involvement in the crimes and his application met the formal requirements for amnesty.
"The applicant was a member of the security forces and according to his evidence he was acting against members of a generally recognised political organisation in countering and resisting the political struggle, which was being carried out against the state and against members of another generally recognised political organisation," it said.
Steyn believed the two men in spite of being in custody, would continue the struggle at the first opportunity and would not be deterred by the normal legal processes.
It was a fact the police were deployed to ensure the government tion movements which came into direct, armed conflict with one another as a result, the committe said.
This fell outside the police's normal functions.
Steyn's actions were associated with and flowed from the police's additional function of keeping the former government in power and protecting the liberation movements' political opponents.
At the time both the police and the African National Congress regarded one another as targets and Steyn's act was directed at a political opponent.
He was an Inkatha Freedom Party supporter while Msweni was a well-known ANC member and Mthethwa a combatant under his command.
Steyns act was not carried out under orders.
"However the applicant reported his actions to a senior officer, who congratulated him. There was even an attempt to conceal the incident, which indicates later approval of his actions by his commanding officer," the committee said.
The relationship between Steyn's act and his political objectives had to be judged in the light of the acrimonious relationship between the liberation movements and the police. Both were for the other a legitimate target in the struggle to achieve a political say and the combating of that struggle.
"In view of the aforegoing, the applicant's application for amnesty succeeds," the committee said.
Sebiloane, a member of Umkhonto weSizwe's special operations unit, applied for amnesty on two counts of attempted murder and one of being in possession of an unlicensed firearm and ammunition, of which he was convicted after injuring two policemen involved in his arrest.
Sebiloane, on instructions from now Defence Minister Joe Modise, established a self-defence unit in Orlando West, Soweto, after his return from exile.
Sebiloane, injured Constables F P van Heerden and J Oosthuizen in a shoot-out when police stopped the car he was travelling in on May 25, 1991.
The amnesty committee said the pertinent question to consider was why he had shot at the police.
Sebiloane contended he was trying to avoid arrest because if he was captured, he feared many of his SDU activities would be revealed.
The important duties he had been instructed to carry out by his commander - to create the SDU and train new recruits to use weapons to protect the community - would also cease.
The committee found Sebiloane's fears were not unreasonable.
He considered his duties in the SDU critical to protect the community - which had been engulfed by violence and which the ANC believed the government and its structures were trying to destabilise.
"This application is clearly distinguishable from the case of a person who possessed a firearm for personal use and shot at the police in order to avoid being arrested for possessing such a firearm without a licence," the committee said.
"Having considered all the material evidence, we are therefore satisfied that the offences committed were acts associated with a political objective, committed in the course of the conflict of the past."
Thyido and Mkuhlwa applied for amnesty in respect of their convictions for the attempted murder of Bongani Anderson Mpisane, the murder of a child, Solethu Ngxumza, and of unlawful possession of a firearm in Khayelitsha on August 29, 1992.
Thyido was sentenced to nine years' and Mkuhlwa to 13 years' imprisonment.
Thyido was an executive member of the ANC Youth League in Khayelitsha and a leader of a SDU, but had been suspended by the ANCYL because of alleged criminal misconduct. Mkuhlwa was an ANC member in Khayelitsha and a branch commander of the Khayelitsha and Nyanga east SDU.
Evidence was led that as a result of conflict between the police's internal stability unit and SDUs, it was decided to raise money to arm the local SDU. Mpisane, also an ANC and SDU member, was appointed to receive money but was suspected of misappropriating the funds.
The committee noted the amnesty applicants claimed in a written submission their political objective had been "to protect my people and to make sure that there was no mismanagement of funds belonging to SDU members".
The committee found attacking a fellow SDU member suspected of misappropriation of funds "cannot be said to be an act associated with a political objective committed in the course of the conflict of the past, as required by the Act".
When Thyido and Mkuhlwa gave evidence, "they advanced a completely different reason for the attack on Mpisane. They said that they believed that he was an informer of the ISU".
The committee said it had difficulties believing that Mpisane was an informer on the basis of the reasons given.
It noted when the applicants had gone to Mpisane's home to ask about a meeting he was allegedly having with the ISU, they had been "armed to the teeth with weapons".
They testified when they accosted Mpisane outside his shop, he resisted and attempted to run away. As he did so Thyido and their companion Malizole Mtshagia fired several shots at him and then left without ascertaining whether he had been hit.
"On a consideration of all the evidence, we are satisfied that there was no justification for shooting at Mr Mpisane, who was attempting to run away from them, the committe found.
"This occurred in an area used and occupied by members of the public and the reckless manner in which a firearm was used resulted in the death of the child Solethu.
"The offences committed by the applicants were not associated with a political objective and were not committed in the course of the conflicts of the past. Their applications for amnesty are therefore refused."