New warship to benefit regional defence: NZ PM

New Zealand Prime Minister Helen Clark says a close relationship with Australia benefits both Australia and New Zealand.

Ms Clark says the country's newest warship will benefit regional missions involving Australia.

HMNZS Canterbury was commissioned in Melbourne this morning.

It is the first of seven ships to be built as part of a $450 million contract.

Ms Clark says the two countries have a long history of defence cooperation.

"Australia's our closest defence partner and I'm sure they'll very much welcome this capability," she said.

"We can see that with deployments we've had in quite recent times with Timor and with the Solomon Islands, a vessel like this would have been very, very useful."

Also, Ms Clark says her country will achieve more in tackling global warming if it cooperates with Australia.

She highlighted efforts to reduce carbon emissions across the Tasman, at a business luncheon in Melbourne.

She says both countries are already benefiting from their close relationship.