The committee also heard one of the plotters, former CP politician Clive Derby-Lewis, had tea with friends and then went shopping with his wife after learning of Hani's assassination.
Derby-Lewis has confessed to jointly planning Hani's murder with Polish immigrant Janusz Walus, and supplying the weapon Walus used to shoot the SACP leader outside his Boksburg home in April 1993.
The two right-wingers, who were sentenced to death for the murder, are seeking amnesty.
Derby-Lewis told the amnesty committee in Pretoria he sought a meeting with Treurnicht, a doctor of theology, before Hani's assassination, in an attempt to resolve several issues that were troubling him.
"One of the things that concerned me was that, in terms of the teachings of the Bible, it was our duty to fight the anti-Christ.
"I had to make to it clear in my own mind that the act of war that I was finally prompted into doing was justifiable."
He said he enjoyed a close relationship with Treurnicht and they had often met to discuss deep theological issues. When he met the CP leader to discuss the issue of murder, he mentioned no names, he said.
"The impression I got from (him) was that under certain circumstances it would be permissable to even kill in the battle against the anti-Christ." Treurnicht died shortly after Hani's murder.
Derby-Lewis said it was hoped Hani's death would plunge the country into chaos, allowing the right-wing to seize power.
The National Party had betrayed its mandate by first scrapping its separate development policy and then unbanning the liberation movements, opening the way for a communist takeover of the government.
Walus and he discussed the worsening situation in the country after meeting for the first time during a by-election in Harrismith in the Free State.
"We discussed how best we could strike a crippling blow against the communist leadership as the real enemy. It was obvious to us that Chris Hani, as the leader of the Communist Party, was the real threat to our future and that of the Republic of South Africa."
It was agreed Walus would handle the logistics of carrying out the assassination. Derby-Lewis furnished him with Hani's address from a list of addresses of political figures and journalists his wife had obtained.
Derby-Lewis said he obtained an unlicenced Z88 9mm automatic pistol from close friend Faan Venter, ostensibly for his own protection, since he had already survived several attempts on his life.
When he went to Cape Town on March 19, 1993 to attend a meeting of the President's Council, of which he was a member, he took the pistol with him to have a silencer fitted.
"The reason for the silencer was to allow me to practice with it at home without disturbing the neighbours, and also to supply me with some element of surprise in the event of an MK or Apla attack on my home."
It was this pistol that he was later to give to Walus during discussions on a date for the assassination.
"We ruled out an attempt over the Easter weekend because that was when people would be at home and in their gardens. This could cause a dangerous situation."
On April 10, the day of the murder, he and his wife Gaye went to the Venters for tea after he tried unsuccessfully to get hold of Walus.
"We had just about finished having tea on the lawn when the telephone rang. Faan's wife went to answer it. She let out a shriek. She shouted that Hani had been shot dead... it had come over the news.
"I got a terrible shock. I thought, jeepers, has something come to our rescue. We don't have to do what we planned.
"We finished off our tea and then we left to do some shopping."
It was only the next day, when he saw Walus' photograph in the newspapers, that he realised the right-winger had jumped the gun and gone ahead with the assassination.
He planned to call an urgent meeting of the CP parliamentary caucus to confess to his involvement in the assassination, but was arrested before he could do so.
Questioned by committee members on the CP's reported condemnation of the murder, Derby-Lewis said the party had set up a legal aid fund to pay for the costs of his criminal trial.
"The actions of the CP were all I needed to indicate their support for me," he said.