Evidence from a hotel room occupied by New Zealand league players at the centre of a sexual assault investigation might have been destroyed because the complaint was made to police after cleaners had removed sheets.

A young woman who alleged she was assaulted by up to five members of the team at a Wellington hotel last Sunday night reported the matter to Lower Hutt detectives at 10.45am on Monday. But by 7.30am that day the hotel's cleaners had already collected numerous bedsheets and washed them, with the Kiwis players checking out at 6.45am for a flight to England.

Authorities are now analysing security camera footage. Lower Hutt police who initially attended the scene did not ask for the footage, but Wellington detectives who have taken over the investigation have obtained the tapes.

A Wellington police spokeswoman refused to confirm or deny suggestions the complainant is 16. "All we will say is that she is a young lady," she said.

It is not known whether any players or team officials will have to undergo DNA testing.

Hotel staff remain stunned at the allegation, with the Kiwis' behaviour said to be exemplary during their six-day stay. After suffering an embarrassing 58-0 defeat to Australia, the players returned to the inn and assembled for dinner in a booked room. One bar was open but no player was seen in it, and it closed at 8pm. The alleged assault occurred between 9pm and 11pm. There was no complaint made by the woman to any of the estimated 20 staff working at that time.

No Kiwis players were seen intoxicated or acting rowdily that evening, and staff reported nothing unusual in their manner at a 6am breakfast on Monday. Cleaners told police there were no signs in the room that anything untoward had happened.