SYDNEY - Australia's ruling Coalition won a spectacular victory in a federal election on Saturday (May 18) after voters backed its economic record and roundly rejected Labor's ambitious agenda to overhaul taxes and tackle climate change.

Despite opinion surveys consistently showing that the Liberal-National Coalition was set to lose, Prime Minister Scott Morrison pulled off the upset with a disciplined campaign that squarely focused on the economy and on voter concerns about Labor leader Bill Shorten.

Appearing jubilant alongside his wife and two daughters, Mr Morrison, a devout Christian, announced victory by declaring: "I have always believed in miracles."

"Tonight is not about me... Tonight is about every single Australian who depends on their Government to put them first."

With 71 per cent of the vote counted last night, it was not clear whether the Coalition would win a narrow majority or would be forced to depend on the backing of independent MPs. ABC News predicted that the Coalition had won 74 seats in the 151-member Lower House, compared with 65 for Labor. Another five were won by independents, one by the Greens, and six were too close to call.

Mr Morrison, 51, has only been Prime Minister since August after an internal Liberal party coup led to the toppling of Malcolm Turnbull. A social conservative, Mr Morrison presented himself during the campaign as an ordinary, sports-loving unpretentious father whose main priority was the economy and jobs.

Mr Shorten, a former union leader who has led Labor since 2013, phoned Mr Morrison to concede defeat and then announced that he would stand aside as Opposition leader. He urged the country to finally a adopt a plan to tackle climate change.

"I am disappointed," he said.

"We campaigned on a positive vision… Clearly on climate action, amongst others, parts of our nation remain deeply divided. For the sake of the next generation, Australia must find a way forward on climate change."

Australia has enjoyed a world-record 27 years of continuous economic growth and unemployment remains relatively low.

But opinion surveys indicated that voters were angry at the Coalition's toppling of successive leaders - Tony Abbott and Mr Turnbull - during the past six years.

Surveys in Australia are typically highly accurate, but analysts suggested a switch away from landlines to mobile phones in recent years has made it hard for polling groups to find reliable voter samples from across the nation's vast geography.

The Coalition ran on its economic credentials and its promise to cut taxes as well as returning the budget to surplus next year.

But Mr Morrison largely avoided proposing significant changes. In contrast, Labor proposed an ambitious - and politically risky - set of proposals, including higher taxes for property investors as well as plans to boost health and education spending and to substantially cut carbon emissions and boost renewable energy.

Most analysts said the result yesterday indicated that voters were fearful of Labor's agenda and preferred to avoid significant change.

"It looks as if it is almost impossible to come from opposition as a big target," political commentator Barrie Cassidy said on ABC News.

Former longstanding Liberal Prime Minister John Howard said he believed voters were put off by Labor's attempts to "denigrate" high-earners and large corporations.

"Australians reject the politics of class division," he told Sky News.

Despite Australia's strong economy, wages are stagnant, power prices are high, and there are concerns about the global economic uncertainty. In addition, the Coalition seized on concerns about the nation's falling house prices to warn that Labor's changes to property taxes would further weaken the sector.

But the ruling Coalition will not have a majority in the Upper House, or Senate, and will need to rely on minor parties and independent MPs to pass legislation.

Despite Mr Morrison's win, former Prime Minister Tony Abbott, a staunch conservative and MP since 1994, lost his seat in Sydney to an independent Zali Steggall. Mr Abbott has been a leading political voice for conservatives who oppose same-sex marriage and strong action on climate change and support the British monarchy.

"I'd rather be a loser than a quitter," he said after losing.

Ms Stegall, a former Olympic skier, presented herself as a Liberal-style candidate who supports action on climate change.

"We have a new beginning for our environment," she said.

Mr Morrison, a former Tourism Australia managing director, will now hold a strong command over the party after pulling off the win that few thought possible, including his own MPs. There will be high hopes that he will lead a united party and that Australia's leadership circus - which has involved internal party coups against four Prime Ministers in less than a decade - will finally be over.

"This is Morrison's victory," said senior Liberal MP Arthur Sinodinos. "He worked hard for it - and he's done it."