Wicha Mahakhun, chairman of a commission sub-committee set-up to investigate the allegation, has told journalists that initial evidence has been sent to Thai authorities from the Australian Securities and Investment Commission (ASIC).

Kingsgate, whose Chatree mine 280 kilometres north of Bangkok has come under scrutiny over environmental concerns, denies the allegation.

Asked whether Kingsgate was aware that ASIC had sent initial evidence to Thai authorities, the company's chief executive officer Greg Foulis said in response: "As this question relates to the activities of ASIC, it is best directed at them."

ASIC head of corporate affairs Matthew Abbott said he could not comment on Kingsgate or whether ASIC had sent information to its Thai counterpart, the Office of the Securities and Exchange Commission.

Mr Abbott referred media inquiries to the Australian Federal Police.

A spokeswoman for the Australian Federal Police declined to comment.

Mr Foulis said Kingsgate had always acted in accordance with Thai mining laws and categorically stated that the company had never made an improper payment in return for a mining lease in Thailand.

He said the Sydney-based company would fully co-operate with Thai authorities.

"Kingsgate adheres to strict corporate government principles and company accounts are audited annually by internationally recognised auditors," Mr Foulis said.

Thai authorities suspended the Chatree mine in January this year over alleged concerns for the health of thousands of villagers living nearby.

The mine is operated by Akara Resources Public Company, a subsidiary of Kingsgate.

The 44-day suspension was the main contributor to Kingsgate's after tax loss blow out to $147 million for the 2015 full year, up from the previous year's $97.6 million in fiscal year 2014.

Kingsgate denied in January that the mine had caused arsenic and manganese levels to rise in villagers, saying it was stunned by the suspension.

The company's website says it has an "outstanding occupational and health record coupled with stringent environmental controls that help underpin the existing operations".

Almost 100 members of a residential group living near the mine told Thai authorities this week their quality of life had improved because of the mine's employment and development funds, and they suffered no adverse health effects from living near the mine.

Kingsgate's chairman Ross Smyth-Kirk in August announced plans for the company to expand its gold mining operations in south-east Asia, including Thailand, Indonesia Papua New Guinea and Vietnam.

He was quoted by the Bangkok Post as saying his company was waiting for Thailand's government to establish a policy for gold mining.

Thailand has not opened any gold mine concessions for private companies for eight years.

But Akara and other subsidiaries of Kingsgate have submitted 107 applications for special prospecting licenses with the Thai government, including mine lease renewals for quartz and sliver, the Bangkok Post reported in August.

Kingsgate has had operations in Thailand since 1987.

The Chatree mine was the first and largest gold mine in Thailand that opened in 2001.

"Kingsgate has built and successfully operated the world class Chatree gold mine in Thailand for more than 14 years," Mr Foulis said.

"We look forward to making a meaningful and ongoing economic contribution to the Kingdom of Thailand," he said.

with Sarah Danckert