Previously unseen documents have revealed the top 10 worst pubs and clubs in New South Wales for money laundering, where millions of dollars were "washed" through pokies in just seven weeks.

The suburban venues, located mostly in Western Sydney, were hosting "distinct organised groups undertaking suspicious activity" who were contributing to "large-scale money laundering", the documents reveal.

Greens MLC Cate Faehrmann, who requested the documents through parliament, said it showed how much authorities knew about the extent of crime-related money laundering going on across the state.

The key document is the result of an Anti-Money Laundering Project, run by NSW Liquor and Gaming and the NSW Crime Commission, and conducted over seven weeks soon after the COVID lockdown lifted in October 2021.

It reveals investigators suspected $5.5 million was laundered through 178 venues in Greater Sydney between 11 October and 29 November 2021.

Ten venues accounted for 41 per cent of that money.

Investigators found 344 suspicious transactions at the Canterbury League Club in Belmore, 273 at Bankstown Sports Club, and 183 at Mt Pritchard & District Community Club.

But the club with the highest dollar value "washed" in the seven weeks was Canterbury League Club with $541,642 exchanged in 344 transactions.

The suspicious transactions were also grouped by Local Government Areas (LGAs), showing most were in Canterbury-Bankstown, then Fairfield City Council, followed by Cumberland, Inner West and Georges River Councils.

"Evidence collected leaves little doubt that electronic gaming machines are being used for large-scale money laundering by organised criminal groups in NSW," the document read.

Documents made public last week show then director of the Independent Liquor and Gaming Authority, Philip Crawford, wrote to the former government raising the alarm about the "very troubling" findings.

Mr Crawford sent the findings of the Anti-Money Laundering Project to then-Gaming Minister Victor Dominello, a month before the portfolio was taken from him and given to Nationals MP Kevin Anderson.

Independent MPs Helen Dalton and Alex Greenwich, as well as Ms Faehrmann have called for a royal commission into money laundering in NSW.

The Anti-Money Laundering Project chose to investigate just after the COVID lockdown lifted, where money laundering was predicted to soar, the investigators said.

Authorities reviewed suspicious transactions flagged by gaming machines, attended clubs and searched CCTV footage.

They found three "distinct organised groups" with suspected links to organised crime.

One syndicate involving about 20 people was run by a man, his wife, and their associate at St Johns Park Bowling Club.

Investigators believe the group had been operating for 10 years and had dealt with "tens of millions" of dollars of dirty money across several NSW pubs and clubs.

One of the members had a Liquor and Gaming Competency Card, meaning the person worked in the gaming industry.

A second syndicate was observed by field officers at Cabra Vale Ex Active Servicemen's Club, where $47,890 in suspicious transactions were flagged over 11 days in October 2021.

"One member hands the unwashed money to a group of females who are playing the machines," the investigation said.

"The females feed the machines and then hand the 'washed' money/tickets to a different member of the group, who then hands the money to a male who appears to be coordinating the syndicate."

Investigators said they had also started looking at a potential third syndicate at the Merrylands Bowling Club.

CCTV showed people putting $50 notes into pokies and withdrawing the money again without gambling it, and others exchanging a bag between cars outside.

The suspected syndicate had links to organised crime and was referred to NSW Police.

The investigators said all of their findings were passed on to NSW Police and the Crime Commission.

RSL & Services Clubs Association, which represent RSL clubs, has been contacted for comment.