Agencies have been working to clean-up an oil spill after a 10-metre boat sank in the Taupō marina on Monday night.

The vessel had a 200-litre load of diesel on board, of which 150 litres spewed out.

'The vessel is believed to have sunk as a result of rainwater filling up the hull, but not being pumped out as a result of the batteries being disconnected while work was carried out on the boat,” says a statement from Waikato Regional Council.

The council says agencies were focused on retrieving the sunken vessel.

A crane was used to uplift, drain and refloat the vessel earlier on Tuesday morning and booms had also been placed around the boat to stop oil from escaping.

A sucker truck was expected to arrive in the afternoon to remove leftover fuel and water from the boat before it was brought onto land.

The Department of Internal Affairs' Taupō Harbour master alongside the Waikato Regional Council, Mercury Energy and Taupō District Council are carrying out the retrieval process.

Council doesn't think the oil spill will be too serious as the leakage will have likely evaporated or dispersed.

It says the spill is unlikely to have 'immediate or lasting impacts” on downstream recreational water users and water consent holders.

The operation to salvage the vessel was expected to be complete on Tuesday afternoon.

-Stuff/ Te Aorewa Rolleston.