New Zealand and Australia will set up a new crisis centre to manage joint responses to natural disasters.

Their response force will initially be based around HMNZS Canterbury, a 9000-tonne, multi-role ship which is the only major asset of that kind available to either country.

Planning will also include greater co-ordination of airlift capabilities, including New Zealand and Australian C130 Hercules and Australia's giant C17 Globemasters.

Australia's two big ships are all but permanently out of the water, leaving their navy with a huge capability gap for at least three years.

The RAN was forced to turn to smaller vessels when help was sought during Cyclone Yasi.

If Yasi had hit the major centres of Cairns and Townsville, shutting down or isolating their hospitals and other emergency services, the navy would have been unable to provide the extensive medical, cargo and heavy-lift facilities carried by the big ships.

Kanimbla and Manoora, bought secondhand from the United States and requiring millions of dollars of repair work before they went into service in 1994, have roughly the same capabilities as Canterbury. But they have been out of service since last September and are not expected to rejoin the fleet.

The third ship, the ageing 5800- tonne Tobruk, is also in "deep maintenance". The 30-year-old heavy landing ship was to have been retired more than a decade ago, but its life has been extended until the arrival in 2014 of the first of the RAN's two huge new amphibious assault ships. Canberra may consider leasing a surplus British ship to help fill the gap.

Until then the Canterbury, capable of carrying four helicopters, hospital facilities and tonnes of stores, will be the only major vessel capable of responding to disasters and other emergencies in the region.

The need for large-scale assets, and their co-ordinated use, was hammered home by floods and Cyclone Yasi in Australia, and the Pike River Mine disaster in New Zealand.

While the RAAF flew mine rescue equipment across the Tasman, New Zealand's offers of defence help were declined by Australia.

" It wasn't actually ultimately required," Defence Minister Wayne Mapp said after meeting counterpart Stephen Smith in Wellington this week. "But what it illustrates is that both of our countries actually expect each other, when times are tough, to make the offer."

Prime Ministers John Key and Julia Gillard meet in Wellington next week, and two New Zealand officers will go to Australia's Deployable Joint Forces Headquarters in Brisbane to join a new planning group.

The joint rapid response force will be ready by the end of next month.

"We have agreed that, to maintain a robust capability to respond to regional contingencies, the Australian and New Zealand defence forces will jointly develop and exercise plans under the rapid response force for a common response to contingencies, including humanitarian assistance and disaster relief," Dr Mapp said.

"This will build on our long history of close operational co-operation and give tangible expression to closer Anzac ties in the modern age."

The region experiences about 12 tropical storms and cyclones a year, as well as tsunamis and political crises such as East Timor and the Solomons.