Tauranga Police will not be arresting anyone following their investigation into allegations of a sexual assault on board the cruise ship Millennium.

A middle aged female passenger on board the ship claimed one of the crew of indecently assaulted her while the liner was at sea.

Police will not be making any arrests in regard to the sexual assault claim on board the Millennium which docked in Tauranga on Friday.

The 294-metre luxury liner sailed from Fiji and docked in Tauranga at 5.12am on Friday.

As a result of police inquiries into the incident there will be no arrest or any persons charged in relation to the investigation, says acting detective senior sergeant Pete Blackwell.

'The matter is complete. We have been in communication with the captain of the ship to advise him of the result of our inquiries.

'There will be some follow up with their own internal policies and practices around the incident that was reported, but the New Zealand Police have no further involvement, and there was no prosecution resulting from the investigation.

Pete says jurisdiction is one factor, but not the only factor in the decision.

'It was thoroughly investigated and there are no charges being brought. There is insufficient evidence to bring a prosecution.”

The Millennium was due to sail to Auckland at 4.15pm on Friday afternoon.

Pete says the ship sailed on time late on Friday.

'We were aware of those tight time lines and our team got right into it from the first opportunity, and it wasn't held up at all.”