Australian opposition leader Tony Abbott, a strong favourite to become prime minister in next month's national elections, urged voters to dump the Labor government he labelled as the worst in the nation's history. Opinion polls suggest Abbott will defeat Prime Minister Kevin Rudd in the September 7 elections, and at his Liberal Party's major rally in Brisbane, he called on voters to give him a chance. "You don't expect miracles, just a government that is competent and trustworthy and a prime minister who doesn't talk down to you," he said as he officially launched his conservative coalition's campaign. "And I'm confident that your expectations can be more than met." Abbott, a former minister in John Howard's government, took the stage to a standing ovation from the party faithful before calling for the removal of "the worst government in our history". However, his speech offered few clues to how his spending promises would be paid for. "I will spend the next two weeks reassuring people that there is a better way, while Mr Rudd will spend the next two weeks trying to scare you about what might happen if he doesn't keep his job," Abbott said. Labor has charged that Abbott, if elected, would "cut to the bone". But Abbott said the country could not afford another term under centre-left Labor, which has switched prime ministers twice in its six years in power. Rudd led Labor to victory in 2007, but was dumped for his then-deputy Julia Gillard in 2010. Gillard won an election that year, but was replaced with Rudd two months ago to try to improve the party's chances at the election. Abbott said his plans for government under a Liberal/National coalition, which would return the budget to surplus and abolish a carbon emissions tax and a mining tax, contrasted with what he called "a confused and chaotic Labor Party". He pledged to fund an interest-free loan scheme to help apprentices train in certain trades, help make certain medicines cheaper for retirees and plough millions of dollars into dementia research.