(Reuters) -The Australian financial crimes regulator said on Monday it opened an investigation into British sports betting giant Entain Plc to assess whether it was complying with anti-money laundering and counter-terrorism financing laws.

The Australian Transaction Reports and Analysis Centre (AUSTRAC) said it began the enforcement investigation after an extensive supervisory campaign covering the whole corporate bookmaking sector, without giving further details.

"Reporting entities have a responsibility to ensure they identify, assess and manage risks of money laundering and terrorism financing, develop adequate processes and devote the necessary resources to comply with their AML/CTF obligations," AUSTRAC Chief Executive Officer Nicole Rose said in a statement.

Online betting has exploded in Australia since the start of the COVID-19 pandemic when physical gambling shopfronts were forced to shut in stop-start lockdowns over nearly two years.

London-listed Entain, which has about one-sixth of Australia's online betting market via the Ladbrokes brand, and larger rival Flutter Entertainment Plc, Australia's largest online betting house which has Sportsbet, reported large revenue increases in calendar 2020 and 2021.

Last month, the British gambling regulator fined Entain 17 million pounds ($19 million), its biggest fine, for what it called "completely unacceptable anti-money laundering and safer gambling failures".

Entain, which in 2021 made an approach to buy certain assets of Australia's No. 2 online betting operator Tabcorp Holdings Ltd, said in a statement the company was cooperating with the investigation.

AUSTRAC had conducted a standard assessment of the company's Australian business' historical Anti-Money Laundering and Counter-Terrorism Financing policies and procedures between July 2016 and June 2020, Entain added.

(Reporting by Byron Kaye in Sydney and Sameer Manekar in Bengaluru; Additional reporting by Riya Sharma in Bengaluru; Editing by Rashmi Aich and Stephen Coates)