Key issues of the third leaders' debate

CANCER

* Asked whether the coalition would match Labor's plans to cover more cancer services on Medicare, the prime minister stressed that in the public system, all treatment is government-funded.

* Mr Shorten suggested the prime minister was out of touch with the out-of-pocket costs people with cancer are facing in the public system.

TAX

* Labor's planned tax reforms were repeatedly spoken about, particularly its proposal to scrap cash rebates for some shareholders at tax time.

* Mr Shorten says the franking credit refunds have been a gift which has become unsustainable.

* Mr Morrison provided a detailed explanation of the refunds, in an effort to highlight that they are aimed at preventing people from being taxed twice.

ECONOMIC MANAGEMENT

* Mr Shorten said a Labor government would not need to create a bigger deficit if there is a sharp downturn in the global economy, because of the extra tax revenue it would be raking in through reforms. He also committed to producing surpluses.

* The prime minister said his government will keep the budget in surplus, but was reminded it will not be known whether it delivered a surplus in 2019/20 as forecast until later next year.

CLIMATE CHANGE

* The issue of climate change again centred around what impact Labor's policies wpuld have on the economy. Mr Shorten again tried to spin the costs to businesses as an investment in the nation's future and highlighted that carbon pollution has been growing under the coalition.

* Mr Morrison said his opponent was taking for granted that there was already action being taken on climate change and increased investment in renewable energy.