An Immigration Service investigator suspects National MP Kanwaljit Singh Bakshi or one of his supporters may have "paid off" the Indian woman at the centre of allegations that he made bogus job offers.

Documents obtained by the Herald show the woman alleged Mr Bakshi made her a false job offer to help her migrate to New Zealand.

But when she and her husband were interviewed in India by an Immigration Service official, they refused to co-operate.

The Immigration Service report on the investigation - obtained under the Official Information Act - says the staff member who tried to interview Kamal Kaur and her husband, Kuldeep Singh, "formed an impression that [they] may have been paid off by Bakshi or one of his supporters".

"There is no evidence to support this impression," the report says.

Mr Bakshi has claimed he was cleared. But the documents show the file was closed because of "insufficient evidence".

The couple's refusal to co-operate was given as a primary reason for the closure.

The report shows Mr Bakshi denied the pay-off allegation when interviewed, and he last night again denied paying off the couple.

But he told the Herald he would not rule out what he described as a "wellwisher" acting without his knowledge.

"I did not authorise anybody to act on my behalf," said Mr Bakshi. "If you have got any wellwisher who can act on your behalf, I can't say."

Mr Bakshi told National whip Nathan Guy he was cleared by the investigation when it was closed in March. He did not reveal that he was accused of paying off the woman.

Prime Minister John Key would not comment last night, but a spokesman said he accepted the explanation given to Mr Guy.

Mrs Kaur and Mr Singh sent a complaint to the New Zealand Sikh Society in September last year alleging Mr Bakshi made a fake job offer to support a 2003 residency application.

The application was denied because she did not meet Immigration requirements and she never left India.

The couple's sworn complaint included supporting documentation including the job offer signed by Mr Bakshi.

Mrs Kaur and Mr Singh said they paid about $25,000 to the immigration agent who arranged the job offer and had not recovered any of the money.

The Sikh Society sent the complaint to the Immigration Service and released details to the media before the election, in which Mr Bakshi was 38th on National's list and so likely to enter Parliament.

An Indian staff member from the Immigration Service's New Delhi office interviewed the couple at a police station there in December.

The investigation report shows Mrs Kaur would not make a formal statement, saying she was "totally satisfied and had nothing more to say".

She refused to sign her statement and would not have her photograph taken for identification purposes.

The Immigration Service also investigated two other job offers Mr Bakshi made to Indians with the same immigration agent in 2003/04.

A woman said she paid the agent about $25,000 and received a job offer from Mr Bakshi. Her application was also declined.

A man said he paid $2500 to the agent and got a job offer from Mr Bakshi.

His application was granted and he came to New Zealand, but never worked or even met Mr Bakshi.

The report says Mr Bakshi denied receiving any money for the job offers or giving false or misleading information to the Immigration Service.

The Immigration Service said the agent, whose name was removed from the report, had left New Zealand but remained a "person of interest".

Between 2001 and 2004, he had lodged 775 applications, of which only 34 were approved.