Nathan Cleary, Tom Trbojevic and more than 30 players have been forced into isolation following a reported positive COVID case at the New South Wales Blues emerging players training camp.

The emerging blues camp is held by the New South Wales Rugby League every season bringing together the future of State of Origin to train under the watchful eye of state coach Brad Fittler and his staff.

It's understood this year that senior members of the New South Wales Blues playing group have also been included in the camp during the lead-up to Christmas.

At this stage, it's not clear which player tested positive.

The Sydney Morning Herald's Christian Nicolussi has confirmed Cleary and Trbojevic are among those players who will need to isolate. It's unclear if James Tedesco was also at the camp after he spoke on Joseph Suaalii's off-season to the NSWRL yesterday.

Both men's and women's players were attending the camp, with Fittler joined by women's coach Kylie Hilder, while staff members included Danny Buderus, Paul McGregor and Mark O'Meley.

According to a NSWRL statement from nearly four weeks ago, the emerging men's squad featured the likes of Junior Amone, Egan Butcher, Joseph Suaalii, Trey Mooney, Haumole Olokau'atu, Will Penisini, Jason Saab, Josh Schuster, Tyrell Sloan, Jayden Sullivan and Izack Tago.

The women's squad was comprised of the under-19s team, while it's unclear which members of the senior women's and senior men's team were involved in the camp.

It's understood all players and staff attending the camp will now be required to take a COVID test and isolate until a negative test is returned.

The camp only allowed vaccinated individuals to attend given current New South Wales government policy for unvaccinated individuals, policy which is set to change from Wednesday December 15.

Up until that date (tomorrow), unvaccinated individuals have been unable to enter stadium precincts within the state. Rules to similar effect will still exist in Queensland and Victoria well into the new year, while the Cronulla Sharks announced yesterday that their club would not be allowing unvaccinated individuals into the club base at Kareela.

It's the second COVID scare for the NRL in less than 24 hours, with the Newcastle Knights' entire playing group forced into isolation and sent home from training yesterday following a cluster at The Argyle in Newcastle, which at least 84 people have already tested positive from.