Twelve alleged sexual assaults were among almost 200 formal complaints laid against taxi drivers and companies with New Zealand Transport Agency in the past year.
Figures released under the Official Information Act show 199 complaints were made to the agency in the year to June 30. They included 12 sexual assault complaints, 22 of inappropriate behaviour, and allegations of fighting with other drivers, falling asleep at the wheel and alcohol and drug use.
The total number of complaints made to the agency fell 9 per cent from 219 in the previous 12 months. The figures don't include complaints made directly to taxi companies or, in more serious cases, to police.
The number of violence complaints increased from two to six - with allegations including threatening a passenger with a knife, intentionally striking a passenger with a vehicle, and assaulting a female special needs passenger.
Other serious complaints in the year to June included allegations of dangerous driving, drinking and driving, and possession and/or supply of drugs.
In the year to June, eight drivers were referred to police, eight complaints were pursued as civil matters, 10 drivers had their licences revoked, 27 drivers and companies received infringement notices, and 31 drivers received written warnings.
The NZTA took no further action on 91 complaints and referred 28 to the taxi companies concerned.
Taxi Federation executive director Roger Heale said he was pleased the overall number of complaints was down, and said most were minor and dealt with internally. However, an internal investigation would be launched regarding sexual assaults.
Cameras had helped "hugely" in reducing sexual assault complaints, including false complaints, he said.
But some companies not associated with the federation had non-functional or poor-quality cameras, he said.
NZTA spokesman Anthony Frith said annual background checks were undertaken on all taxi drivers to determine whether they are "of proper character".
This included police checks and looking into prior complaints.
Rape Prevention Education executive director Kim McGregor said the sexual allegations were a huge concern.
"We have been advising women, particularly who have been drinking, to get a taxi home for safety reasons. So if they're not safe in a taxi, this is a really big concern for us."
It was likely to be only the tip of the iceberg, with only one in 10 sexual assaults usually reported.
Cameras in taxis were there for safety and it was of real concern if they were not functional, she said.
Tips to stay safe in taxis
*Note down the number of the taxi displayed in the vehicle and text it to a friend.
*Take a photo of the driver and send it to a friend.
*Get out of the car a few doors down from your destination, as long as it's safe.
*Request a female driver, and wait in a safe area until she arrives.
Source: Rape Prevention Education