South Sydney great Nathan Merritt is fighting for his life after being hospitalised on Friday afternoon. 

Merritt was found unresponsive and was taken to Royal Prince Alfred Hospital in Camperdown. 

The 40-year-old is on life support and his condition is listed as serious. 

Merritt was one of South Sydney's best and most popular players of the modern era, scoring 146 tries in 218 matches from 2002 to 2014. 

His 219 appearances is fourth all-time for the league's oldest club and he retired as the most prolific tryscorer in Rabbitohs history.

Merritt also spent two seasons with Cronulla earlier in his career. 

His 154 career tries is the equal 12th most of all time. 

The Redfern product was the league's top tryscorer in 2006 and 2011, with the former arguably his greatest feat given South Sydney finished with the wooden spoon. 

Merritt represented City Origin and the Indigenous All Stars and earned one cap for New South Wales in 2013. 

He has remained active since his retirement from the NRL and played in last week's Koori Knockout.