Updated 1.48pm: A promise from National that no Defence Force camps or bases will close, if it's re-elected - but it's not committing any new money to the military.

John Key's made the announcement on a visit Palmerston North to support National's candidate, Jono Naylor - who's currently the local mayor.

National's hoping the defence commitment will bolster support from the local Linton and Ohakea bases, where personnel have been concerned about potential cutbacks.

But rather than announcing new funding, National says it'll continue with its already-announced plans to modernise military bases and upgrade weapons and technology.

The only new aspect of its policy is greater clarity for civilian companies, from construction and weaponry down to catering, about the processes for winning government contracts.

Defence spokesman Jonathan Coleman says National will also make it easier for civilian companies to work together with the Defence Force on government contracts.

"Sometimes we have to go offshore. Sometimes New Zealand companies might get into a tender process where realistically, they might not be able to provide the sort of thing we are looking for."