SYDNEY (AFP) - Australia's election is set to be a nail-biter with two polls published on Monday (May 9) suggesting it is too close to call as the first full day of campaigning got underway.

Conservative Prime Minister Malcolm Turnbull, in the top job for less than a year, on Sunday called the national vote for July 2, saying there was a "clear choice" between him and Labor opposition leader Bill Shorten.

But opinion polls indicate a tight race, with an Ipsos one in The Sydney Morning Herald showing Turnbull's Liberal/National coalition winning 51 to 49 per cent but a Newspoll in The Australian had Labor ahead by the same margin.

Australian elections, where voting is mandatory, are traditionally close, and the conservatives - then led by Tony Abbott - won the last one in September 2013 by 53.5 per cent to 46.5 per cent.

As parliament was Monday officially dissolved in Canberra, the Ipsos poll of 1,410 voters taken after last week's national budget put Turnbull ahead as preferred prime minister but with his personal rating sliding.

Turnbull was in front 51 per cent to Shorten's 29 per cent as preferred prime minister, but down on his 54 per cent standing of last month.

The Newspoll of 1,739 people taken over the same time frame also found Turnbull was seen as the better prime minister - by 49 per cent to Shorten's 27 per cent.

But it had the Labor Party ahead 51-49 in an election.

Asked about the polls on Monday, Turnbull noted that his government had eight weeks to make its case to the Australian people.

"We will be talking about our national economic plan every single day," he told reporters in Queensland state, on one of the nation's longest-ever election campaigns.

"Jobs and growth. Confidence. Australia - its future. That's what this election is about." Australia is charting a rocky path away from mining dependence after an unprecedented resources investment boom that has helped the nation avoid a recession for 25 years.

The nation has had a "revolving door" of prime ministers in recent years, with four different people serving as leader since 2013 as parties removed sitting prime ministers.

This is the first election campaign as the head of their parties for both Shorten and Turnbull, who ousted colleague Abbott in a Liberal Party room vote last September.