Labour MP Charles Chauvel says New Zealand's migrant policy discriminates against seasonal workers with HIV.
A report issued by the United Nations Global Commission on HIV and the Law has found that punitive laws are among factors fuelling the AIDS epidemic.
At present, seasonal workers must provide the results of an HIV test, and those who test positive are automatically excluded from the scheme.
Mr Chauvel, who is on the commission, says the policy increases the stigma and spread of HIV in the migrants' home countries.
He is calling on the New Zealand Government to change the law and let those who test positive into the scheme.