WELLINGTON - The New Zealand government on Tuesday announced new curbs on the number of immigrants to the country, following a long-running debate over the effect of migration on the economy.

Immigration Minister Michael Woodhouse said the changes to the New Zealand Residence Programme (NZRP) for the next two years were part of a regular review of the numbers, but opposition lawmakers said the government was running scared of public opinion polls.

The changes included temporarily closing the parent category to new applications-a measure that will directly affect a huge number of Chinese parents wanting to live with their migrant offspring.

However, Woodhouse's statement did not detail how temporary the closure would be.

Overall the number of residence approvals for the next two years would be cut from 90,000-100,000 down to 85,000-95,000.

The government was also raising the requirements for skilled migrants and cutting the number of places for capped family categories from 5,500 to 2,000.

"Migrants make a valuable contribution to New Zealand both culturally and economically, and the government periodically reviews all our immigration settings to make sure they are working as intended," Woodhouse said.

"Today's announcement demonstrates the government is taking a responsible, pragmatic approach to managing immigration."

While, economic forecasters including the Reserve Bank of New Zealand have credited migration with bolstering the country's healthy economic growth, others have questioned whether the infrastructure is coping with record numbers of migrants.

The concerns have fuelled disquiet over issues such as the worsening housing crisis, which is rippling out from the largest city of Auckland.

The opposition New Zealand First party said the government had been panicked by polls on immigration and had suddenly reversed its stance that the country's immigration settings were about right.

"The plain fact is after years of denial, their polling is telling them the public are concerned," New Zealand First leader Winston Peters said in a statement.

The government had "created a massive problem" by bringing in huge numbers of unskilled migrants, and the parent category meant their parents had "flooded in also," straining the provision of housing, health and education, said Peters.

"Over 15 years we have taken in over 87,000 parent migrants who have no requirements to contribute to the economy while they receive free access to public health immediately, and superannuation after just 10 years here," he said.

The business lobby group, Business New Zealand, said the changes were an encouraging sign of progress towards a migration system that benefited the workforce and the country generally.

"It is positive that the government has taken on board some of the concerns of employers regarding the skill base of those achieving permanent residency status," Business New Zealand chief executive Kirk Hope said in a statement.