The Rugby League Players Association is investigating security and welfare issues during and after Sunday's Sharks-Dragons match, including allegations that drunken fans abused St George Illawarra forward Joel Thompson in front of his wife and two-year-old daughter and threatened to urinate on their car as they were leaving Southern Cross Group Stadium.

The incident occurred after players were forced to walk from the dressing rooms under the western grandstand to a car park in the adjoining Sharkies Leagues Club, which is on the opposite side of the ground.

Cronulla officials have also been asked to explain why fans of all ages were on the field while the teams were waiting for a post-match presentation of the Monty Porter Memorial Cup after the Sharks' 30-2 win.

The RLPA has also raised welfare concerns after Dragons under-20s players were forced to spend their half-time break on the field and had to wait up to 60 minutes after their match to access the dressing room because the club's NRL team was using it. While no incident is known to have occurred when the fans invaded the field, Cronulla chief executive Lyall Gorman admitted there had been potential safety issues.