May 18 appears the most likely date for Australia's next election at which the conservative government faces an uphill battle to win a third three-year term.
Government sources have told media that Prime Minister Scott Morrison will not call an election on Sunday, which had been widely anticipated.
Sunday was the most likely choice if Morrison were to opt for the first of three dates available to him - May 11, May 18 and May 25. While many commentators had previously thought May 11 the most likely election date, May 18 would give the ruling coalition another week to use government money to advertise its policies and achievements.
Once an election is called, the coalition becomes a caretaker government and would need the approval of the center-left Labor Party opposition if taxpayers were to continue funding of what are described as government public information campaigns.
Morrison on Sunday defended his government's spending and accused Labor of using government coffers to pay for its own advertising while it was a caretaker administration ahead of its defeat in the 2013 election.
He gave no clue on Sunday to the election date.
"The election will be called in April and the election will be held in May," Morrison told reporters in his hometown Sydney.
"We're not doing this with any haste and we're not doing it with any delay," he added.
The government has been trailing Labor in opinion polls for most of the last three years since it scraped back into power with a single-seat majority at an election that cost it 14 seats. The ruling coalition has since lost another two seats in the 150-seat House of Representatives and now has only 74 lawmakers in the chamber where parties form government. Labor has 69 lawmakers and the remainder are minor parties or independent legislators.
Prime ministers traditionally call elections on a Sunday. The campaigns last at least 33 days and officially start a few days after the date is announced.
Monday is the last day that Morrison can call a May 11 election. But doing that would mean senators who had flown to the Australian capital Canberra for committee hearings starting Monday would be sent home that day.
The Australian Electoral Commission website says May 18 is the last possible date for the election because counting votes can take six weeks and must be finalized by June 30. The government would have to invest in more commission resources to cope with a tighter deadline created by a May 25 election.
But Morrison said on Sunday that May 25 remained an option.
Prime ministers usually keep their choices of election dates a tightly guarded secret in an effort to put the opposition at a tactical disadvantage.
Opposition leader Bill Shorten told reporters Morrison was delaying the election because "this government wants to spend tens of millions of dollars on TV advertising to pump up their own tires."