Police say they are growing increasingly concerned for the welfare of a British tourist who has gone missing in New Zealand. Detectives are investigating the disappearance of 22-year-old Grace Millane, who was last seen in Auckland on Saturday night. The backpacker, reported to be from Essex, has not been in contact with her family for several days, including on her 22nd birthday on Sunday. Detective Inspector Scott Beard, of Auckland City Police, said Ms Millane's father was on his way to New Zealand, and said her family were understandably "distraught". "Clearly this is a very stressful time for Grace's family and the longer she remains missing, the more our concern grows for her safety and wellbeing," he said. CCTV image issued by Auckland City Police shows Grace Millane at Auckland's Sky City entertainment complex Credit: Auckland City Police Ms Millane is said to have been in New Zealand for about two weeks, and was staying at a backpackers' hostel in Auckland city centre. Police have released a CCTV image of the last known sighting of her at 7.15pm on Saturday at entertainment complex Sky City. A number of unconfirmed sightings have been reported to detectives. Members of Ms Millane's family have shared appeals for information on Facebook, and Mr Beard said more than 20 staff were working on the case. A spokesman for the Foreign Office said: "We are providing consular support to the family in the UK, and working with the New Zealand Police in relation to reports of a missing British national in New Zealand."