Prime Minister Bill English says any drastic cuts to immigration would be bad for New Zealand's economic growth.

Watch Bill English talk to Guyon Espiner on Morning Report here:

Mr English told Morning Report that, with near-full employment in some areas, slashing immigration when there was a need for workers would not be sensible.

Labour, which is expected to announce its immigration policy shortly, has accused the National government of failing to adequately plan for what has been record immigration - putting pressure on infrastructure, housing, and public services.

"We've been planning for a growing economy and adapting to that growth, because it's been more sustained I think than people expected - more successful than people expected," Mr English said.

"We need the people to do the jobs. Right now, the demands in the construction sector are as high as they have ever been."

He said if Labour announced a plan to cut net migration by 20,000-30,000 people a year, as has been reported, it would stall the economy.

"We have to build the houses, we have to build the roads and the water pipes to support the houses - that's for people who are here now.

"Slashing the immigration - whatever you think of it - slashing it when you need the people to do the jobs that must be done, it doesn't make any sense."