Plans for Australia's Super Rugby franchises to play a domestic competition were put on hold on Monday and training halted after tough new government measures to contain the coronavirus.
The four teams, plus the axed Western Force, were due to kick off a round robin tournament on 3 April after the southern hemisphere championship, which features 15 teams from five countries, was suspended.
But that has now been delayed until at least 1 May following government recommendations against non-essential domestic travel and the shutdown of a range of businesses countrywide.
Western Australia, where the Western Force are based, will also close its borders on Tuesday, effectively preventing movement in or out of the state without observing two-week quarantine periods.
Rugby Australia chief Raelene Castle said the game's stakeholders were united behind the move.
"The decision to postpone the restart of the competition until May 1 is in line with the suspension of all community rugby in Australia and will give us the opportunity to review our position across the whole rugby landscape in a month's time," she said.
"While this is having an unprecedented impact on our sport and many other sports, this is bigger than sport and that is why we will continue to put the health and welfare of our people above anything else."
The Western Force, Reds, Waratahs, Melbourne Rebels and Brumbies have all stopped training for an initial two weeks, with modified programmes resuming after that.
A halt was called to the broader Super Rugby competition after seven rounds this month when New Zealand and Australia said all inbound travellers must self-isolate for 14 days.
Australia has recorded more than 1 600 cases and seven deaths from Covid-19.
Most sporting codes in Australia, including cricket, basketball, and Aussie Rules, have cancelled or suspended their seasons, although rugby league and football continue to press ahead without spectators.