Rugby Championship organisers have ordered players and staff to isolate in their hotels amid a Covid-19 outbreak in Brisbane ahead of the final match of the competition.

Despite the new cases, the Queensland government has not enforced a lockdown.

Brisbane is the scheduled location for the opening Ashes Test in December.

New Zealand, South Africa, Argentina and hosts Australia played in a double-header in Townsville last weekend and wrap up the competition on the Gold Coast on Saturday.

"We're not allowed out of the hotel except for essentials or medical visits," said All Blacks assistant coach Scott McLeod.

"It's something that's unexpected but we've had it before and dealt with it really quickly."

Cricket's Sheffield Shield match has been postponed until later in the season and, while acknowledging the match could have proceeded under the current public health settings, Tasmania said they had taken a "cautious and considered approach" and opted to fly home.

Brisbane, which is the capital of Queensland, is also due to host National Rugby League's Grand Final on Sunday between the Penrith Panthers and South Sydney Rabbitohs.

Four new cases were reported in Queensland on Tuesday.

The only health measure to be re-introduced so far is a return to mandatory mask-wearing in indoor settings for those in the Brisbane and Moreton Bay Areas.

Queensland chief health officer Jeannette Young said officials could order a lockdown if more cases emerge over the next couple of days.