A total of 124 migrant sex workers were interviewed for the study, which was conducted predominantly in Auckland.
Catherine Healy, the collective's national co-ordinator, said there were an estimated 1700 prostitutes in Auckland, but it was not known how many were holders of temporary visas.
Although prostitution has been decriminalised here, it is illegal for those on temporary visas, such as students or visitors, to work in the sex industry.
"The findings suggests there are no signs that migrant sex workers here are victims of trafficking," Ms Healy said.
Immigration fraud and compliance manager Peter Elms said the study had helped to "lift the veil on employment practices" within the sex industry.
"While the report's findings in respect to working conditions was positive, there were a number of concerns raised, including that 5 per cent of those interviewed stated their workplace did not allow them to refuse clients and that 5 per cent did not have easy access to their passports," Mr Elms said. "Unfortunately the survey did not clarify what was meant by not having easy access and so it is difficult to draw any conclusions based on this one factor alone."
The US State Department last year named New Zealand as a "source country" for sex trafficking of underaged forced labour, and said a small number of girls and boys were trafficked domestically as street prostitutes.
It said foreign women from China and Southeast Asia were recruited to become prostitutes and may be at risk of coercive practices.
AUT University researcher Danae Anderson said she was aware of cases where sex workers have had their passports taken by their employer.
"They were told they will be reported to immigration if they complained about their conditions," she said.
Foreign prostitutes
57%: On student, work or visitor visa
86%: From Asia
26%: Came to New Zealand "to study"
35%: Knew someone living here
76%: Did sex work to pay household bills
5%: Could not refuse clients and did not have access to their passports
Source: Research on migrant sex workers in New Zealand