Australia's financial markets remain well regulated, but deceptions such as the Whitehaven Coal hoax don't improve its image, the corporate regulator says.

Australian Securities and Investments Commission (ASIC) deputy chair Belinda Gibson told a senate estimates hearing ASIC was investigating whether laws were broken during a hoax by environmental activist Jonathan Moylan.

In January, Mr Moylan sent a press release to media outlets claiming ANZ Bank had withdrawn a $1.2 billion loan from Whitehaven - and the hoax temporarily wiped $314 million from the miner's share price.

She says he hasn't been charged.

Ms Gibson was asked whether hoaxes impacted the reputation of Australia's sharemarket.

"Anything disorderly like that cannot enhance the reputation," Ms Gibson told the senate committee on Wednesday.

But Ms Gibson said such events were infrequent and were unlikely to lead to a general loss of confidence or make overseas investors nervous.

"I would have thought that our discussions overseas leads to the view that our market is well regulated and well respected, but it is not a matter ever to be relaxed about the issue," she said.

Ms Gibson said the regulator treated "very seriously" statements that were false and affected a company's share price.

The penalties for misleading the market - 10 years or $750,000 or both - were among the heaviest under the Corporations Act, Ms Gibson said.