The Government has instructed officials to investigate the whereabouts of Tongan nationals in New Zealand who have undeclared criminal histories.
Police in Tonga have identified 172 cases where officers cleared criminal records of people wanting to obtain visitors' visas into New Zealand or Australia.
Immigration Minister Michael Woodhouse said on Tuesday that an immediate hold has been put on Tongan visa applications that need a police clearance until Immigration New Zealand can be satisfied with the integrity of the Tongan police clearance process.
Mr Woodhouse said about 40 people with false clearances may be in New Zealand and has asked officials to put the highest priority on finding any Tongan nationals who have committed serious crimes.
The minister said it is totally unacceptable for anyone to enter New Zealand by providing misleading information and is taking the matter very seriously.
Michael Woodhouse said deportation is a possible outcome if any of the Tongan nationals in New Zealand with undeclared criminal histories are found to have committed serious crimes.
The minister told Radio New Zealand's Checkpoint programme on Tuesday while officials are tracking down about 40 people with false clearances, they do not have those people's date of birth records to work from.
"Until we get that information, we can't be sure about who is actually subject to these police check letters. What I am advised is the majority of the criminal convictions are for relatively minor offences such as disorderly behaviour, drunkenness and theft."
Tonga's Police Commissioner Grant O'Fee found out last week that officers had cleared the records of former criminals. He said all police records have since been manually searched and it has been discovered that a manslaughter conviction was cleared.
The New Zealander said he does know whether the officers were bribed.
"The only way to determine how broad this issue was was to manually search the entire collection, which has now been completed.
"I have no evidence to suggest that anyone was paid; I'm not saying they weren't, I'm just simply saying I have no evidence to substantiate that yet and I'm still exploring that."
Mr O'Fee said action will be taken in relation to the officers involved once he has a report from the Solicitor-General.
Earlier, the commissioner said he expected the number of records cleared would exceed 50.