The Brumbies are set to open the Canberra Stadium gates for their interstate derby against the NSW Waratahs, which will be played hours before advice kicks in from the federal government to cancel public gatherings of 500 people.

The federal government says it will be advising people to avoid gatherings from Monday, which has given the Brumbies approval to play their home game in front of what will likely be the biggest crowd of their season.

Rugby Australia and SANZAAR have agreed to have the match go ahead.

The crowd number will almost certainly take a hit, but McKellar hopes fans still support what is usually a feisty contest.

"I'm sure we'll get through the weekend and there will be some further discussions [about coronavirus] next week," McKellar said.

"But I'm a rugby coach. I can't worry about those sorts of things, that's for the health authorities and experts. All I can do is prepare a football team well and make sure we're ready to play.

"Ideally that's in front of 15,000 people. [There are] good individual match ups, afternoon rugby idea for families, good weather ... get out there and watch it."

Brumbies coaches and players are being continually monitored and tested for coronavirus symptoms.

They could also limit contact with fans at the game to minimise the risk to the public and the players.

But the fact they will be free to play came as a major relief, especially after a season so far of illness, smoke, fire, thunder and circumstances outside of the Brumbies' control.

Disappointing crowd numbers will have a significant financial impact on the Brumbies, who are already walking a tight line with their money.

The game against the Waratahs has in the past been the golden egg.

This year they have offered $500 bus vouchers and free tickets to regional clubs to celebrate country round and to encourage fans to attend the day-time contest.

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The Brumbies are hoping on-field form can help turnaround low attendance figures, with an average of just 7268 watching the first three home games of the year.

The Brumbies have won four of their first five games, putting the club on the verge of equalling its best start to a season in seven years, and the equal best since winning the Super Rugby title in 2004.

The chance to do so against the Waratahs will make it even sweeter.

"The Tahs and the Brumbies don't really like each other. That's fine," McKellar said.

"You'd play the Tahs every week if you could. They'd be the same with us, that's not disrespectful. They're just good games to be involved in. These are the sort of games you get excited about."

Rugby supporters have been walking away from the game in recent years, but no one could have predicted the wild ride in the capital to start this year.

It began when the team was forced to move pre-season training to Newcastle to avoid the toxic smoke filling the Canberra air.

Week one of the regular season was overshadowed by an ACT state of emergency, which was declared just hours before the Brumbies' clash against the Queensland Reds on January 31.

The fires raging near the ACT border threatened homes in the south, so people's focus was understandably elsewhere rather than on the earliest start to a season in Super Rugby history.

The 7436 who did turn up sweltered through 40-degree temperatures.

Week two was relatively incident free, although it rained on game day., That had another impact on the crowd, with 7098 fans trickling through the gates.

Surely things got better in week three? Wrong. A thunderstorm hit Canberra, with lightning striking behind the stadium and giving fans another reason not to attend.

In the end 7270 watched the heartbreak against the Otago Highlanders, with the Dunedin-based side scoring after the siren to snatch a two-point win.

Week four was the outbreak of the mumps. Players, coaches and staff put in quarantine, and some ruled out of a defining win against the Waikato Chiefs in Hamilton, New Zealand.

The bye gave everyone a reprieve, but even then they couldn't avoid the drama. Coronavirus forced Super Rugby officials to act, moving the Brumbies' game against the Japan Sunwolves from Osaka to Wollongong.

The icing on the cake was the unusual and prohibitive kick-off time of 2.45pm.

Through of all that the Brumbies have managed to win four of five games and are on the verge of recording their best start to a season in seven years.

But we get round seven and the coronavirus threatened to lock the Canberra Stadium gates after the government decided to cancel all non-essential organised events of 500 people or more.

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