Prime Minister John Key has been questioned about why no National party MPs will be at an event to support the homeless tonight.

Lifewise, the Child Poverty Action Group and Park Up For Homes have organised the events which see families park up and sleep in their cars for a night.

MORE: Labour MPs to sleep in cars for homeless

The first event is this evening at Mangere town centre, organisers say John Key and his wife were invited.

MPs from both the Green party and Labour party will be at the event.

Mr Key told media today he wasn't aware of any National party MPs going and said it wouldn't be a directive from him anyway, it would be their own decision.

He also rebutted claims the party doesn't look after the poor as well as the rich.

Three more events are scheduled to be held on June 25 in Wellington central, and the Auckland suburbs of Otara and Mangere.