Brisbane Heat's Chris Lynn and Dan Lawrence had to keep their distance from team-mates during the Big Bash defeat by Sydney Thunder following a possible bio-bubble breach.

Cricket Australia (CA) is investigating after Heat captain Lynn and Essex batsman Lawrence reportedly posed for a photograph with a fan

on Saturday.

They used a separate changing room and designated seats in the dugout in Canberra, and could not join any celebrations of wickets.

CA head of security Sean Carroll said: "It is important we maintain the integrity of the bio-secure hub to ensure the safety of the public, players, staff and officials and minimise issues associated with travel between state borders during the tournament.

"We appreciate that this has been a challenging year for everyone but we must insist on our bio-security measures being respected and followed so as not to jeopardise public health and safety or the viability of the tournament."

Lynn made 69 off 44 balls and Lawrence - called up to the England Test squad last week for January's tour of Sri Lanka - 20 off 19 as the Heat posted 178-6 at Manuka Oval.

Thunder recovered from 1-2 and 22-3 to win by four wickets thanks to Daniel Sam's brutal unbeaten 65 off 25 balls.

He hit three fours and seven sixes, including three in succession off Ben Laughlin to seal a remarkable victory.