Immigration New Zealand is calling for organisations working with migrants to dob in overstayers and is warning temporary workers who outstay their permits that they will face the full force of the law.

The Herald reported yesterday that migrant advocacy group Migrante Aotearoa was seeing an increasing number of its members becoming overstayers and spokesman Dennis Maga said many Filipino migrant workers would rather work underground here than go back to the Philippines if their permits were not renewed.

Immigration NZ head Andrew Annakin said the service was deeply concerned by that statement.

"Overstaying and resultant compliance action impose significant costs on the New Zealand taxpayer," he said.

"If Migrante Aotearoa knows the names of people living unlawfully in New Zealand, it should alert Immigration NZ or the police."

Mr Annakin said a significant number of Filipino migrants entered New Zealand in the skilled migrant category with a work-to-residence visa, which gave them nine months to search for skilled employment.

"It is made clear to people before they take up these visas that the outcome of their residence application depends on them obtaining a skilled job.

"If they are unable to find employment they should either return to their home country, or they may be able to apply for a labour market-tested work permit if they have lower skilled employment and there are not New Zealanders available to undertake the work."

He said work permits would generally be declined if suitable New Zealanders were available to fill a vacancy - and the recession had resulted in an increasing number of Kiwis seeking employment.

Philippine consul-general Emilie Shi is asking the Government to let Filipino workers who have come on temporary permits to fill jobs that the locals didn't want to do rather than repatriate them.