The Prime Minister is holding firm on Auckland light rail.

Chris Hipkins was grilled by Opposition Leader Chris Luxon on his commitment to the project as the two leaders faced-off in Question Time.

Luxon questioned whether the $30-billion project was a good use of money in a cost-of-living crisis.

Hipkins defended it, saying it's a once-in-a-generation investment in the city.

He says we have to get serious about Auckland having first-world public transport infrastructure, which the National Party don't seem to want.