Truckies blasting their horns have joined drivers of campervan and SUVs festooned with anti-government banners to converge on Australia's Parliament House in a protest calling for new elections.
Police estimated 350 vehicles - mostly trucks - in at least three slow-moving convoys motored through the centre of the national capital and past the Parliament and Prime Minister Julia Gillard's nearby official residence.
The cacophony of horns blared across the front lawns of Parliament where hundreds of protesters gathered late morning to call for new elections and an end to the government's plan to tax major polluters for every ton of carbon gas they emit. Banners included "CO2 is good stuff" and "democracy is dead."
An organizer of the so-called Convoy of No-Confidence, Kate Stuart, said more trucks were en route to Canberra although they were unsure how many.
Some had travelled in a convoy for 5700km from Port Hedland in the northwest to protest against an eclectic range of government policies.
Cattle rancher Rashida Khan and her partner Len Baker joined the Port Hedland convoy in the northern city of Darwin then drove their pickup truck 4000km to spend two days in Canberra before driving home.
Khan, 23, said she is angry at the carbon tax as well as the government's recent decision to suspend live cattle exports to Indonesia due to concerns about slaughterhouse cruelty.
"You can get away with a lot with the Australian people, they're very laid back," Khan told The Associated Press. "But after 12 months of this sort of government - that's all unstable and upside down - it's terrible," she added.
The protest organized by a truck drivers' group argues that Gillard's minority government is not legitimate because it has relied since elections a year ago on the support of the minority Greens party and independent lawmakers to form a slim majority in the House of Representatives.
Trucks travelling in 11 convoys from around the country were to have converged on Canberra for a far larger rally.
Organizer and truck driver Mick Pattel said some of those conveys had been delayed and some trucks turned back as part of a deliberate strategy to limit disruption to Canberra traffic and because of the high fuel costs in reaching the city.
"There was massive concern about gridlock and traffic chaos and I think we've done everything we can to avoid that," Pattel told demonstrators.
Gillard's centre-left Labor Party has suffered in opinion polls since she was re-elected and then broke a promise that she would not introduce a carbon tax.
The tax is scheduled to be introduced from July 1, 2012 - a year before Australia's next general elections are due.
While the major opposition parties oppose the tax, Gillard has sufficient support to pass the legislation through Parliament with the endorsement of Greens and independent lawmakers.
