AUSTRAC is undertaking an inquiry into casino junket tours, which it expects to finalise by the end of the year.

At the same time, Crown has disclosed to the stock exchange its Melbourne casino is being examined by AUSTRAC.

Crown said it would respond to all information requests in support of the investigation and fully co-operate.

The casino giant is also facing a NSW gaming regulator inquiry into whether it is suitable to operate a new venue in Sydney.

AUSTRAC chief Nicole Rose said Crown Melbourne submitted 50,000 reports of suspicious matters to her agency in 2019, representing 43 per of all casino reports.

They includes such things as transactions of over $10,000.

"We informed Crown in the last couple of weeks ... we have some serious concerns and junkets are certainly one of those concerns," Ms Rose told a Senate inquiry on Tuesday.

The suspicious matter reports were added to AUSTRAC's intelligence systems and made available to law enforcement agencies.

Ms Rose said there were many challenges in dealing with such matters.

"Our regulation manages domestic issues," she said.

"Junkets are often offshore and managed offshore and we don't have the reach into them that we would like.

"It is something we are looking at through the risk assessment ... we are talking to the (home affairs) department. We don't have the visibility of where it is coming from."

Asked whether AUSTRAC had gone easy on Crown, Ms Rose said: "I don't think AUSTRAC has ever been accused of doing anything softly softly."

"We will be working on the enforcement matter ... these matters can take up to two years, they are incredibly complex."

The 2017 version of AUSTRAC's casino junkets risk assessment said casinos were broadly aware of and comply with anti-money laundering rules.

Ms Rose said there was now a greater understanding of the risks involved, which required the assessment to be updated.

Australian Associated Press