The first of the Navy's four new inshore patrol vessels will finally be handed over on Thursday after a series of delays and problems which have made them nearly two years overdue.

The HMNZS Rotoiti will be handed over to the Navy on Thursday and commissioned on Friday in Whangarei before sailing to the naval base in Devonport for sea trials and training on April 24.

The remaining three inshore vessels are expected by the end of May. They will be used for maritime surveillance, including customs, fisheries, conservation and police work. They will also have a role in disaster relief.

The vessels are among seven new ships ordered in 2004 under the $500 million Project Protector. The ships were all due by the end of 2007 - but to date only one, the HMNZS Canterbury - has been commissioned.

The four inshore patrol vessels were built in Whangarei, worth $143 million. The Rotoiti failed its safety tests when trialled in May 2008, requiring further work.

The delivery of the Rotoiti follows a trip by Defence Minister Wayne Mapp to Australia last month to meet the contractors and request they deliver the ships while outstanding contractual problems were sorted.

He criticised the handling of the project by the previous Labour Government, saying the contract was badly thought through and he had arrived to "a mess".

There is no delivery date yet on a further two larger offshore patrol vessels, worth $90 million each. The Government will enter mediation with the contractor, BAe Systems, at the end of May after it was discovered that over time, they would become too heavy for some roles, including work in the Antarctic.

The $177 million 9000-tonne HMNZS Canterbury is also beset with problems - an independent report estimated it needed another $20 million spent on it.

One of the primary causes for the delays with all vessels was the inflatable seaboats carried by the ships, which had to be replaced by the contractor after problems arose with them on the Canterbury.

The Navy is hoping the vessels make the Navy a more attractive option for sailors.

In advice to Dr Mapp last December, the Navy said key personnel were leaving because of the delays in the ships arriving. Dr Mapp said the arrival of the new high-tech vessels would be an incentive to stay in the Navy. "It will make a huge difference. If you're a young officer or seaman, you get to be in charge of a pretty sophisticated vessel."

The contract with BAe Systems specified at least $110 million of the Project Protector contract had to be done in New Zealand. Dr Mapp said that target - set in 2004 - had been exceeded - about $135 million of work was done in New Zealand.