NZ First leader Winston Peters has launched an attack on immigration policy and questioned whether Auckland is becoming "the supercity of sin", linking crime and other problems to immigration from China.

In the speech to a North Shore Grey Power meeting he denied his party was anti-immigrant, saying it was not against bringing in people with skills lacking in New Zealand.

And he pointed to comments by the new premier of China that the biggest challenge facing China was the level of corruption.

"It stands to reason that corruption can be exported and imported," Peters said.

He said the Government was talking of a million more people in Auckland soon "and there is no prize for guessing where most will come from".

He cited a free trade deal that works when it suits China, massive investment in local farms, forests and factories, fast-track schemes for students and rich Chinese tourists, and huge investment in the housing market.

He said when the rich tourists had finished at the blackjack tables or the poker machines at SkyCity casino there was another attraction nearby.

"The Hong Kong born Chow brothers are thoughtfully providing a 15-storey brothel, in what used to be an historic building, just across the road from the casino in the heart of Auckland," Peters said.

"And thanks to our generous student and worker visa schemes the Chow brothers will be able to provide genuine home-grown sex workers for the visitors if that's what they want."

He said "that scurrilous magazine Truth" was "chocker with sex ads" most based in Auckland. Many of the advertisements "in reality represent people trafficking".

The seven deadly sins were alive and well in Auckland and the city was being trashed economically, socially, physically and ethically, he said.

An Asian student cheating industry had emerged, a slave trade was running where immigrants were promised jobs and ended up working for nothing, and some tradespeople were concerned about backyard industries springing up that they could not compete with.

There was "a deafening silence about the impact that high levels of immigration has had, and is having, on the demand for housing, transport, hospitals, schools and other services", Peters said.

He also criticised the policy of allowing the parents of immigrants to qualify for superannuation after 10 years here.

He said one skilled worker from China could come with a wife and a child and bring in both sets of parents.

"You spend your lifetime struggling and you get the same pension and health entitlements as a parent from abroad who comes here at age 55 and contributes nothing," he said.

NZ First policy would tie superannuation to years of residence, so someone here for 10 years would only get a quarter of New Zealand superannuation.

Prime Minister John Key said the speech didn't contain anything new. "This is just more of the same, tired old rhetoric from a tired politician," a spokeswoman for him said.

Labour leader David Shearer said Peters "has his own views, some of which we don't share. It's up to voters to decide the composition of the next Government at the election. My only focus is on asking people to vote Labour."

A Green Party spokesman said "We find the way (Peters) says it reprehensible and of course there's politics in there.

"We just hope a spohisticated discusssion can be had on some of the issues he raises, such as the impact on property prices."