Protests erupted outside the National Party's northern regional convention in Auckland.
Around 50 Auckland Action Against Poverty representatives squared up to police in Mt Wellington, demanding a living wage and universal access to state housing.
One of the protesters was reportedly arrested for trespassing after running past police and trying to enter the Waipuna Conference Centre.
Group spokeswoman Vanessa Cole says the protest was timed with Mother's Day to acknowledge sole mothers, who "face economic punishment from Work and Income".
"We wanted to grill [Prime Minister Bill English] and the party about their lack of work for low income people."
Ms Cole says the protest was also to send a message to other political parties about the poverty "crisis", and says current tactics to solve the issue are not working.
"We believe that social investment is not going to solve the crisis low income people are having. It ignores the root causes of poverty. People need income and work to have dignity."
The National Party conference will continue until Sunday afternoon.