Labour and National are promising to make it easier to build more houses.

The parties are launching joint housing reforms -- saying as many as 100,000 extra homes could go up within the next eight years.

The cross party announcement came from government ministers for housing Megan Woods and the environment David Parker, as well as the National Party's leader Judith Collins and housing spokesperson Nicola Willis.

RNZ's political editor Jane Patterson explains the reforms with Māni Dunlop.