She said her belief was the public expected the Medical Council to deregister doctors who had offended against patients.
"While it is technically possible for the public to find out if someone has been de-registered, most New Zealanders would not know to check," she said.
Health Minister Tony Ryall referred questions to the Medical Council but said he expected the council to consider patient safety paramount.
An example of the issue is former Southland GP Lewis Stephen Gray, who was found guilty in 2001 of disgraceful conduct by medical authorities after forming a sexual relationship with a vulnerable patient.
He was not deregistered and was practicing in Southland until three weeks ago.
"I have moved to Australia and am waiting for my registration over here. But I was working in New Zealand for 11 years since the charges and 15 years since the event," said Gray.
He had worked with conditions until they were removed 15 months ago. The conditions included that he did not work in a sole practice and he informed any employer about his past.
Medical Council spokesman George Symmes said there would be more transparency soon.
"Our online medical register is still very much a work in progress. ...
"We're also wanting to give [patients] the choice of looking at the whole register or only those doctors who are currently practising. Ideally, these are things we'd like to get achieved in the next 6-9 months," said Symmes.
The Herald on Sunday found four doctors who are working with conditions - John Dannefaerd Nealie, Nihal Sydney Gurusinghe, Ramesh Nayar and Gopalrao Chebbi. The Medical Council said there were two more, which we were unable to identify.