The 40-year-old was found dead at an apartment on The Kingsway, Cronulla about 9pm on Thursday.

His death is not being treated as suspicious and there was no evidence of self harm, police say.

Thompson was reportedly found by his teenage daughter.

Australian Rugby League Commission chair Peter Beattie has led tributes for Thompson, saying his death was a loss to the sport.

"A very sad day for rugby league with the passing of NRL star Lance Thompson," Beattie tweeted.

"A much-loved member of the rugby league community. Condolences to his family."

Ashton Sims also used social media to pay tribute to his former St George Illawarra teammate .

"Total loss for words. Lance was one of the toughest forwards I've played with and looked after all of us young guys coming through the (Dragons)," the 33-year-old posted on Twitter.

Former Wests Tigers star Keith Galloway said the red-haired second rower was an idol of his growing up.

"One of my childhood favourites and a local hero who I looked up to and was lucky enough to get to know over the years, champion bloke and player," he tweeted.

Thompson played 239 first grade games with the Dragons (201 matches) and Sharks (38).

He made his first grade debut as a 17-year-old with St George in round 13 1995 against Cronulla before he switched to the Sharks for the 2006 season.

The veteran backrower was forced into early retirement in 2008 as his body broke down after 14 years in the NRL.

At the time, Thompson was battling a knee injury and cited his long-term health and inability to keep up with his young daughter while having a backyard kick as reasons to call it quits at age 30.

He scored a try in his farewell game but Penrith spoiled a fairytale swan song with a 21-20 golden-point win.

A report into Thompson's death will be prepared for the coroner.

AAP

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