Bookmaker Tom Waterhouse has sold his online betting business to British gaming company William Hill.

Waterhouse will receive $34 million for the business, plus an earn-out agreement that could see him receive up to $70 million.

He will also remain managing director of the business.

William Hill earlier this year acquired Sportingbet's Australian business for $670 million.

The company's chief executive Ralph Topping said William Hill had set its sights on becoming Australia's biggest online bookmaker.

"The Sportingbet acquisition gave us a strong and proven platform with an experienced management team," Topping said.

"Acquiring tomwaterhouse.com gives us a rapidly growing business that appeals to a wider customer base."

Waterhouse has been a source of controversy this year owing to a sponsorship deal with the NRL which prompted widespread criticism that gambling was being promoted during TV broadcasts of matches.

He also fronted Racing NSW over the More Joyous inquiry after owner John Singleton made public allegations that Tom Waterhouse had said More Joyous - trained by Tom's mother Gai Waterhouse - could not win the All Aged Stakes on April 27 in which she finished second last.

Tom Waterhouse was cleared of any wrongdoing and stewards found no evidence he had passed on any inside knowledge regarding the mare's condition.