UPDATED: 12.03PM Defence Minister Gerry Brownlee is blaming the last Labour Government for inadequately equipping the Navy.

It follows revelations some Navy boats bought to patrol New Zealand's waters haven't been to sea for years.

Figures obtained by New Zealand First show the Pukaki hasn't been to sea since some time in 2012 and sister ship Taupo since some time in 2013.

New Zealand First Defence spokesman Ron Mark said this year only nine days have been spent by all the navy vessels on fisheries patrol and last year it was only 33 days.

"Excuse me? Either someone's having a very very long holiday or we simply don't have the man power to staff and sail our vessels and I'm picking it's the latter, because the New Zealand is not known for being lazy."

Mr Brownlee said there are too many in-shore patrol vessels and not enough off-shore vessels like the HMNZS Otago and Wellington.

But Mr Mark is questioning why the National Government has done nothing about it.

"And that does not excuse them for explaining why the current vessels have not been at sea, and why we don't have enough sailors, and why we don't have enough money for them to be able to do their jobs."

Mr Mark said it was particularly concerning considering the Government wants to add a further 620,000sq km to the Navy's patrol zone with the creation of the Kermadec Ocean Sanctuary.

“Given we’re responsible for a vast slice of the globe that extends from Antarctica to north of the equator and mid-Tasman to east of the Cook Islands, our Navy is frankly way too small and our seas are mostly unguarded.”

Labour MP Phil Goff is equally concerned but puts the problem down to staff shortages.

He said the Navy doesn't have the skilled staff to man the inshore patrol vessels, something he blames on the Government's civilianisation programme that saw the Navy suffer an attrition rate of 23 per cent.