Malcolm Turnbull is Australia's fifth prime minister in as many years, and after eight months in the top job, declining approval ratings suggest he has proved a disappointment to many voters.

Turnbull called parliamentary elections for July 2 in hopes that his conservative Liberal Party will be able to pull off a victory before public opinion turns against the government further and give him a Senate that is more likely to pass his legislative agenda.

Polls show Turnbull's party is neck-and-neck with the center-left Labor Party, but voters also say they prefer him as prime minister over opposition leader Bill Shorten.

Turnbull, a 61-year-old self-made multimillionaire, took over the reins of power in September from the polarizing Tony Abbott, whose socially conservative stance on many issues had grown unpopular. His removal gave the coalition government an immediate but short-lived bounce in the polls.

The subsequent slide in Turnbull's public support could be partly explained by the high expectations when he took office, said Australian National University political scientist John Wanna.

But apart from ditching the titles of knights and dames that Abbott had restored, Turnbull has not lived up to expectations of more progressive policies.

"Turnbull is more urbane, middle class, cosmopolitan, but he hasn't filled the space with anything," Wanna said. "He took over in early September and we're now in May and he hasn't really put his moniker on anything."

Turnbull has been hamstrung by promises he made to the party's conservative members to ensure their support when he challenged Abbott. He agreed to maintain the government's opposition to gay marriage and to a carbon tax on companies — even though he had previously clashed with right-wing elements in the party on these policies.

The government's re-election would give Turnbull a mandate from the people rather than his party colleagues, allowing him to have new authority to shape government policy.

The Liberal Party's coalition controls 90 of 150 seats in the House of Representatives, where parties that hold the majority of seats form a government, while Labor has 55. In the 76-member Senate, the government has 33 seats — short of a majority — and Labor holds 25.

In a normal election, about half the senators are up for a vote, but in an early election all 76 senators face elections — which Turnbull is betting will give him a greater turnover and more compliant chamber.

"I suspect the Liberals are calculating that if they do get back, they'll have a different Senate to deal with and one that's a lot less oppositional," said Wanna.

Turnbull has long battled a public perception that his wealth puts him out of touch with ordinary folk. His nickname is "the Silvertail," a pejorative Australian term for the privileged elite, and cartoonists often depict him wearing a top hat. Trying to counter this image, he has cultivated a reputation for traveling by trains and buses in cities around Australia, frequently using social media to share his public transport experiences.

He wasn't born into privilege. His father was a Sydney hotel broker who became a single father after his wife abandoned the family when Turnbull was 9 years old. He studied at the University of Sydney before attending Brasenose College, Oxford, as a Rhodes scholar.

Turnbull became a household name in Australia as a lawyer in the 1980s when he succeeded in blocking a British government attempt to prevent Australian publication of "Spycatcher," a memoir by former British intelligence officer Peter Wright.

He also worked as a journalist, investment banker and venture capitalist before he was elected to Parliament in 2004 to represent the Sydney electoral division of Wentworth, the wealthiest in Australia. Turnbull was the richest member of Parliament until mining magnate Clive Palmer was elected in 2013.

He led the Australian Republican Movement, which argues for severing Australia's constitutional ties with Britain and appointing an Australian citizen as president. The status quo was maintained in a 1999 referendum, and Turnbull's sometimes abrasive style was blamed by some as contributing to its failure.