About 80 trucks are on their way to Parliament House in Canberra in the first phase of a "convoy of no confidence" against the Gillard government.
But the convoy protest did not all go according to plan this morning.
A 5.30am start was delayed until about 6.15am because of insufficient numbers.
The first line of trucks are travelling along Northbourne Avenue, the main northern approach route to the city centre.
They will cross Lake Burley Griffin before using State Circle, which encircles Parliament House, to make their protest.
Later, a rally on the lawns in front of the Parliament will be addressed by Opposition Leader Tony Abbott.
The convoy protest comes as parliament sits for four days and Prime Minister Julia Gillard, whose stocks are sagging in opinion polls, faces community anger over her broken promise on the carbon tax and changes to the diesel fuel rebate.
A petition will be presented calling for a double-dissolution election even though there has been no legislative trigger for such an option.
Mr Abbott, who joined the convoy at Marulan 120 kilometres north of Canberra yesterday, said the convoy comprised "salt of the earth Australians who feel they are being ripped off by a bad government".
THE smaller-than-promised crowd at yesterday's Convoy of No Confidence rally was enraged by the allegation that their numbers were depleted because the police had turned back a convoy of trucks at the border - even though rally organisers knew it was not true.
The Nationals senator Barnaby Joyce and Liberal frontbencher Sophie Mirabella repeated the accusation that the police had prevented trucking protesters from attending and broadcaster Alan Jones said a truck convoy two kilometres long had been stopped at the border, and that this was ''the most disgraceful thing that has ever been done to our democracy''.
About 200 trucks arrived in Canberra in convoys from around Australia, including Port Hedland and Darwin, but organisers had been predicting many more.