Greens co-leader Metiria Turei will be interviewed by an investigator from the Ministry of Social Development after admitting she misled social services while on a benefit.
This month she confessed she sub-let her home and lied to Work and Income, as a single mum claiming benefits in the 90s.
After writing to the ministry to say she would co-operate in any investigation, she spoke to an investigator over the phone today.
"During our phone call, I made myself available to be interviewed about my case.
"We are in the process of confirming the details of that meeting, but it will take place next week."
Earlier, Ms Turei said she would not condemn individuals who were struggling on the benefit and lying to social services, saying instead she wants to "fix the system".
On TVNZ1's Breakfast this morning, Ms Turei said "a few hundred" people had come to her with similar stories while currently receiving the benefit.
She described their situation as "desperate" and that they felt "like there's no way out."
"These people are my constituents, I take care of them," Ms Turei said.
When asked by Jack Tame if she condones those people breaking the law she said, "I don't condemn these people for doing what I did".
"If we have a welfare system that drives people into such deep poverty... then what kind of system have we built?
"I'm not interested in judging these individual parents. I want to fix the system that forces them into these terrible, awful choices.
"My job as a law maker is to make sure that every law in this country is fair, and just, and does not punish people unnecessary simply because they're poor."
She said it was difficult for people to go to WINZ if they were struggling due to it having "a culture of fear and punishment that forces these people to be terrified."
"We've cracked open the stories, let people come and describe their circumstances, get their full entitlements but make sure they are not punished for doing what they need to do to feed their kids."
The government has confirmed a WINZ investigation into the matter is under way.
On Q+A last week, Turei says she is unsure how much money is at the centre of the investigation, but it was possibly about $20 to $50 dollars a week over about a three-year period.