Townsville is on standby to host the NRL grand final on October 3 if the NRL is forced to shift the decider from Suncorp Stadium after new cases of COVID-19 were found in south-east Queensland.
On Saturday ARL commission chairman Peter V'landys confirmed that the next 24 to 48 hours are crucial to plans to hold the NRL grand final in Brisbane for the first time.
Five cases of community transmission were detected in the state on Saturday with the Queensland government flagging a lockdown if the virus spreads over the weekend.
It could mean a shift further north for the NRL, although V'landys refused to put a deadline on when the decision would be made.
"We're absolutely concerned, it's so unpredictable this Delta virus, it's so contagious," he told 2GB radio on Saturday.
"It only took one person in NSW and look at where we are now, over 1500 cases a day.
"We don't take anything for granted and the next 24 to 48 hours for us is crucial."
A snap lockdown would also trigger tighter biosecurity restrictions for teams still in the finals who remain in Queensland in their respective hubs.
With three weeks until the decider the NRL is walking a tightrope to play the grand final in front of a full crowd.
In 2020 the grand final was played at Stadium Australia with a 50 per cent crowd capacity of 37,303.
However, 53,000 fans can pack into Suncorp Stadium under no COVID-19 restrictions - more than double that of Queensland Country Bank Stadium's maximum capacity of 25,000.
"At the moment it's programmed for Suncorp and if all goes to plan it'll be at Suncorp with a full crowd," V'landys said.
"But if something happens and there's a lockdown in Queensland and Brisbane, and we can't have a crowd, we do have the option at the moment to go to Townsville.
"We want a crowd at the game, so we'll do whatever we can to have a crowd."
Should the decider be moved it would mark a historic double for Far North Queensland after Townsville hosted game one of the State of Origin series earlier this season.