"We've had a number of persons nominated as possibles - you get that in any inquiry - and what you have to do is either brick them in or show that they couldn't have committed the offence.
"We're still following a number of what we think are interesting leads. We certainly haven't given up hope at all, we're still confident we'll get a successful result," he said.
Meanwhile, police are looking for a 1980s to 1990s light-coloured stationwagon that was seen near the museum at the time of the burglary.
There are renewed concerns the medals may have left the country.
"We're keeping an open mind on the subject, but there's no evidence the medals have gone overseas," said Mr O'Rourke. He said in the past couple of weeks, border controls had turned up a number of medals legitimately.
"It shows the system's working."
- NZPA