The electoral office of NSW Labor MP Noreen Hay has been raided by the Australian Federal Police (AFP) over enrolment fraud allegations.

AFP officers executed a search warrant on her office on Crown St, Wollongong, on Wednesday.

The AFP told the ABC it had received a referral from the Australian Electoral Commission on December 8 last year "relating to allegations of enrolment fraud".

A spokesperson said it would be inappropriate to comment further on the ongoing investigation.

Opposition Leader Luke Foley's office said Ms Hay had informed him of the search.

"We understand the Member and her office have offered the AFP every assistance in the investigation," a spokesman said in a statement.

"We have asked for further information which we anticipate will be provided tomorrow."

Ms Hay has not responded to repeated requests for comment.

While the AFP said the raid related to electoral fraud, the details of the allegations are still not known. It is also unclear whether the investigation relates directly to Ms Hay.

Ms Hay has been a controversial figure in the NSW Labor Party.

In 2008, she was involved in an investigation by the Independent Commission Against Corruption (ICAC), codenamed Operation Atlas.

The ICAC was inquiring into allegations of corrupt conduct within Wollongong City Council.

While there was no adverse finding made against Ms Hay, the ICAC publicly stated that it had not "cleared" her.

MP under fire over 2013 China trip

Ms Hay has more recently come under attack in the NSW Parliament for her links to Chinese education agency, Shinyway.

Government whip Dr Peter Phelps told Parliament Ms Hay had promoted the unregulated Beijing agency and recruited overseas students during a 2013 visit to China, then failed to declare the trip.

Dr Phelps referred to a story on the ABC's Four Corners program in April about Australia's universities and foreign students, including the Shinyway Education Group, which reportedly promised a "top-line education but paid dodgy agents offshore to drum up business ... then turned a blind eye to cheating ... and turned out poorly trained graduates".

"In this regard, I am deeply disturbed to learn of the role that the Member for Wollongong has played in promoting Shinyway's business," Dr Phelps said.

"On the morning of 18 September, 2013, a three-person delegation, led by the Member for Wollongong, visited the Shinyway Education Group."

Dr Phelps said Ms Hay was then guest of honour at the launch of Shinyway Education in Sydney on October 24, which he said "raises some interesting questions".

"Perhaps the most important question is: What is (Opposition Leader Luke) Foley going to do about this? He has made much of the need for reform in Labor and now is the opportunity for him to put his money where his mouth is," he said.

"My concern is about Shinyway, who is promoting it in this country and whether they should be promoting it. It raises an interesting question about this trip to China. Who paid for the airfare, accommodation, meals and transport?

"If Ms Hay did not pay for these elements, why is there nothing in her pecuniary interest returns indicating travel or gifts received?"

Hay 'not keeping secret' from Parliament

In a letter of explanation to the Legislative Assembly, Ms Hay said Dr Phelps had "sought to impugn my reputation with innuendo and smear" in relation to the trip, on which she was accompanied by her personal assistant Kiley Martin.

"I absolutely refute any suggestion of wrongdoing on my part and can provide the Parliament with a copy of my e-ticket, which clearly shows that the trip was paid for by me, and confirmation of my hotel booking," she told Parliament.

Ms Hay said she would also provide a copy of an invitation letter from the CPC Nanhu Committee and the people's government of Nanhu district, along with correspondence with then-premier Barry O'Farrell that described the visit to "China businesses and educators, including the vice-chancellor of Jiaxing University".

"You can hardly claim I was keeping this a secret from the Government or the Parliament," she said.

"I was not the beneficiary of any complimentary travel or expenses, hence that is why I did not declare it in my pecuniary interest declaration.

"[Dr] Phelps should do the honourable thing and apologise for abusing parliamentary privilege and making baseless personal attacks against myself and my staff."