Workmates last saw barmaid on birthday eve

Work colleagues of dead Wanganui woman Tania McKenzie knew something was wrong when the normally punctual barmaid did not turn up for work.

Their concern turned to horror when they found out her body had been discovered in the Whanganui River.

Her body was found by a member of the public at 10.30am on Friday - the day of her 20th birthday - in the city section of the Whanganui.

She was last seen leaving her workplace, the Red Lion Inn on the opposite side of the river to where she was found, around midnight on Thursday. More than 30 detectives from throughout the lower North Island have been brought into investigate the death.

Detective Senior Sergeant Mike Oxnam said Ms McKenzie died from massive head injuries.

He would not say whether he believed she was dead before entering the water, nor whether he thought she was the victim of a sexually motivated crime.

"A large number of people are co-operating with us and assisting us with our inquiry."

Mr Oxnam said it was likely the attack happened between 1am and 6am on Friday and called for anyone in the area at that time to contact police.

Red Lion Inn manager Lisa Martin described Ms McKenzie, who had worked at the Inn for the past 10 months, as a joy to work with.

"She is a bubbly, outgoing, fun person."

Ms McKenzie finished her shift at the tavern at 10pm then stayed on for a few drinks to celebrate her impending birthday.

"She was in high spirits. We all knew it was her birthday."

Ms Martin said it was out of character when Ms McKenzie did not turn up for work the following day.

"She is a committed loyal worker who always called in if she was running late or couldn't make it to work.

"When we couldn't contact her we were a little bit worried."

But when Ms Martin learned that Ms McKenzie's body had been found, her concern turned to horror.