The Brumbies have been given clearance by local government to accommodate 6,000 fans at Canberra Stadium when they host the Super Rugby AU final next weekend.
The figure represents a doubling of the capacity of the 25,000-seater stadium in Australia's capital, which has been restricted because of social distancing measures put in place to contain the spread of COVID-19.
"The Brumbies would like to thank the ACT Government and the Chief Health Officer for this morning's decision," said chief executive Phil Thomson.
"It's very rare to be able to host a grand final and to allow as many people from our region to be there and be a part of it next Saturday night is something we're really excited about."
The Brumbies won both of their Super Rugby titles in front of packed houses at Canberra Stadium in 2001 and 2004 but have not hosted a title decider since.
They earned the right to host this year's final of the domestic Australian competition by topping the regular season standings and will face the Queensland Reds or Melbourne Rebels, who meet in a playoff in Brisbane on Saturday.