Australia's Labor party is expected to defeat the ruling Liberal-National Coalition in the federal election today, despite opinion surveys indicating a last-minute tightening of the contest.

On the eve of the election, a series of national polls indicated Labor had a 51 per cent to 49 per cent lead and was on track to win a small majority in the 151-member Lower House. A poll by market research company Ipsos published yesterday indicated the Coalition had recovered ground since last month, when it trailed by 47 per cent to 53 per cent.

However, a number of surveys indicated that people are increasingly supportive of Labor leader Bill Shorten becoming prime minister, despite his low approval ratings.

According to the Ipsos survey, 40 per cent of people would prefer Mr Shorten as prime minister, compared with 47 per cent support for Prime Minister Scott Morrison. Mr Shorten had trailed by 11 percentage points last month.

Despite Australia enjoying a world-record 27 years of uninterrupted economic growth, voters appear inclined to switch to Labor following six tumultuous years in which the Coalition has churned through three separate leaders.

But this followed Labor's own run of internal coups. If Mr Shorten, as expected, wins today, he will become Australia's seventh prime minister since 2010.

Mr Morrison, who became leader last August after the party ousted Mr Malcolm Turnbull following a bruising internal battle instigated by the party's hard-line conservative wing, has run a disciplined campaign, largely attempting to focus on his two strengths: the electorate's belief that the Liberal party's economic credentials are better than Labor's, and his status as the preferred Prime Minister.

Mr Morrison, 51, has attacked Labor's plans to increase taxes for property investors and those on higher incomes, and has attempted to present the election as a direct choice between himself and Mr Shorten, 52.

In contrast, Mr Shorten has - unlike Mr Morrison - largely shared the spotlight with his fellow frontbenchers and pointed to the strength of Labor's "team".

He has attacked the Coalition for pandering to big businesses and the wealthy, and for lacking a credible plan to tackle climate change.

Labor has adopted a relatively bold agenda, seeking to use its proposed tax increases to lift spending on health, childcare and education.

Political commentator Michelle Grattan said Mr Shorten's agenda was Labor's most ambitious in more than 40 years.

In contrast, she said, the Coalition had not presented a "comprehensive blueprint".

"Mr Morrison's campaign has been all about the negatives, why this is 'not the time for change', conjuring up fears about what Labor's tax agenda would bring," she wrote on The Conversation website. "It's been focused on caution, the need for people to avoid the unknown in uncertain times."

The vote today will also determine the make-up of the 76-member Senate.

Neither side is expected to gain a majority but the Chamber will include up to nine MPs from The Greens party, as well as candidates from small parties such as Ms Pauline Hanson's anti-migrant One Nation party and tycoon Clive Palmer's United Australia Party.

The Senate results will be crucial because the Chamber can potentially block significant legislation proposed by the ruling party.

This means that Labor, even if it wins, may struggle to introduce its tax measures, which would then leave it unable to deliver its spending on social services.

Today's election comes just two days after the death of popular former Labor prime minister Bob Hawke. Mr Shorten and Mr Morrison paid tribute to him yesterday.

Mr Hawke's wife Blanche d'Alpuget told Mr Shorten: "There's nothing that would make Bob happier than Labor winning the election. So go out and do it."