But there's an earlier sign: a flurry of government appointments to courts, boards, embassies and commissions in the hours before the Prime Minister hitches a ride to the Governor-General's Yarralumla residence to call an election.

Under caretaker provisions, successive government have refrained from announcing key appointments during an election campaign, prompting an 11th hour rush to clear the decks.

For the more cynically minded, the convention also presents the government with a strategic motivation.

Former Finance Department deputy secretary Stephen Bartos said pre-election appointments were often politically minded, as governments sought to appoint sympathetic voices to key positions.

"It's clearly a case of ministers wanting to get as many people with sympathetic leanings into offices as they can, just in case they lose the election," he said.

"They are also keen to announce them before caretaker because if any appointments are questionable, they are done and dusted before the election campaign official begins and any criticism can be written off as electioneering."

Conveniently, many of the announcements coincide with the conclusion of Senate estimates on Friday.

Mr Bartos said most of the appointments made in recent days would have been planned for months in advance, requiring ministerial sign-off. Some, however, were likely to have involved a quick discussion followed by approval from cabinet.

Here is a taste of appointments announced in the past 24 hours: