New Zealand - A 65 percent increase in the number of foreigners being held in New Zealand prisons in less than a year has sparked calls for better screening of immigrants at its borders and a "first strike and you're out" policy for immigrants who break the law.

Figures given to the Sunday Star-Times by the Corrections Department show that from May 30 last year to April this year, the number of sentenced and remand prisoners describing themselves as non-New Zealanders rose from 402 to 624. The total prison population is 7500.

The number of Chinese prisoners almost doubled, from 35 to 64. Corrections Department figures show there were increases in the number of Britons, Fijians, Indians, Samoans and Tongans, among others, jailed in the past year.

Garth McVicar, from the Sensible Sentencing Trust, said it was time New Zealand took a stand on the issue. He estimated foreigners were costing the country $3 million a year to house in prisons.

"We shouldn't be accepting this in New Zealand, we have enough of our own problems without importing them as well," he said. "It should be a case of first offence, and you're gone, deported. The screening at the border also needs to be improved; we're not checking them carefully enough."

National's law and order spokesman, Simon Power, said background checks on immigrants needed to be improved.

"If those statistics are correct, it's clear we're letting in more and more bad apples," he said.

He did not believe the issue was one of deporting the prisoners before they served their sentences, as they had broken New Zealand laws so should be subject to the country's sentencing and corrections systems.

Corrections Minister Damien O'Connor believed New Zealand's border controls were robust and working. He said the legal system was set up to deal with criminals regardless of their nationality, and as there were a large number of visitors to the country there would inevitably be those who broke the law. He said the issue of deporting criminals sooner had not been discussed.

"The point is, should New Zealanders in jails around the world be brought back to serve their sentence here? Whether we'd be a winner or loser from such a scenario is hard to assess."