He was giving evidence at a sitting of the Truth and Reconciliation Commission at Moutse, Mpumalanga. The incorporation of Moutse in KwaNdebele in the mid-eighties sparked a civil war about plans for independence.
Lerm, who succeeded Gen Christiaan van Niekerk towards the end of 1986, said he was being cast as an aggressor in the area and as a racist. He quoted a newspaper report saying he was implicated in more than 500 killings.
"That is not who I am, " he said. "Today I want to show you the real Hertzog Lerm. I wanted to protect lives and property."
Lerm said there were 4670 cases in the year 1986 to 1987 in KwaNdebele and he had only five detectives and about 45 policemen to investigate them. Appeals to Pretoria for help came to nothing.
"It was an impossible task," he said.
Despite numerous allegations against him, Lerm said, he had never tortured, abducted or murdered anyone.
The unrest worsened because the central government did not give the people political rights, he said, preferring to the use of security forces and emergency regulations to remedy the problem.
People opposed to the SA government were suppressed by about 800 policemen sent from all over the country to enforce the state of emrgency, Lerm said. There were covert operations and human rights violations by this force.
Lerm attributed these excesses to the fact the policemen and their commanders were outsiders, with no feeling of loyalty to the local area or the people. Lerm said he would not accept responsibility for what they did.
He said there were also covert operations, attacks and counter-attacks by supporters of KwaNdebele chief minister Majozi George Mahlangu and his brother and political rival, Prince James Mahlangu.
As for his own men, Lerm said, he did not believe they were guilty of human rights violations, and he was proud of their efforts in difficult circumstances.
Lerm said the Parsons commission of inquiry into the violence in KwaNdebele, which implicated him, was a political ploy to discredit him in the eyes of the people.
It succeeded because the SA government used the press "and the press loves to exaggerate".
Asked by commissioners about evidence that KwaNdebele police used to "soften up" areas for attacks by the vigilante group Mbokodo by riding through in Hippos and firing teargas into houses and yards, Lerm said the KwaNdebele Police did not have Hippos.
These were the vehicles used by SA policemen, he said.
Denying he was a racist, Lerm said: "The KwaNdebele people are lovely people. They are very cross with me, but I love them. I love their lovely paintings and beadwork."
In conclusion, Lerm said: "The Truth and Reconciliation Commission is the most wonderful thing that has happened to South Africa. I can already see the change."
He referred to the kindness shown him by officials and the audience at the sitting.