"When these young people climbed up on the roof of the house I thought to myself 'they're real heroes, there's no medals in this for them'," he said.
"If they're going to do that the least I can do is put my lights up on them to ensure their safety so that they don't get taken away in darkness."
He said things had happened "when the lights went out" at previous protests in Glen Innes that he did not want to see repeated.
"There have been previous occasions when women have been severely beaten by police while trying to prevent those houses being removed. I'm not going to let that happen on my watch."
The protesters would be safe as long as a Member of Parliament had his lights trained on the roof, he said.
He acknowledged that a police officer had knocked on his window and asked him to moved his car. He said he had rolled his window down slightly so they could talk.
"I said I would move it once the girls were off the roof. I rolled the window up and that's the position I took."
Police denied that he said this.
Furthermore, Harawira said the truck would not have been able to move anyway.
"The truck hadn't started up, the gates hadn't been opened, there were still people milling around. It wasn't possible for the truck to go anywhere so I can't have been obstructing it. There wasn't even anyone in the driver's seat."
Giving his opening address in te reo, Harawira said he had a duty to take a stand, as an MP who stood for the interests of the poor and dispossessed.
"To see what has happened to some of those communities, and in particular this one here in Glen Innes, should pain the heart of every New Zealander," he said through an interpreter.
"What's happening to those families calls on New Zealanders to do something to stop it."
Harawira is expected to call about a dozen witnesses before Judge Stan Thorburn.
The hearing continues.