A LIBERAL candidate has admitted he is "not across" his party's direct action policy on climate change, despite his party declaring it one of the key issues of the coming election.

Liberal candidate for Wakefield Tom Zorich was challenged in a Sky News debate last night to explain the policy, which would replace Labor's emissions trading scheme if it were abolished.

"Look, I'm not across all those issues," Mr Zorich said.

"As a candidate, and a businessman, I'm not across everything.

"I haven't got an answer for you."

Coalition Leader Tony Abbott has declared the September 7 election a referendum on the carbon tax, which his party claims is destroying competitiveness in the Australian economy.

Watch the Sky News video here

The gaffe echoes Liberal candidate for Greenway Jaymes Diaz's failure last week to name the six points of his party's immigration policy, which promises to "stop the boats".

Last week, the Coalition was forced to reject claims it would need to spend billions more on its climate change policy to achieve promised cuts to carbon pollution.

The Climate Institute found the Coalition's policy would result in Australia's carbon emissions increasing by the end of the decade, rather than reducing as promised.

Mr Abbott said he simply didn't accept the report.

The Coalition will spend a maximum $3.2 billion over four years funding carbon emission-reduction activities, like revegetation and improving soil carbon as part of direct action.

Both Labor and the Coalition have agreed to cut CO2 emissions by 5 per cent of 2000 levels by 2020, and up to 25 per cent depending on global action.

Wakefield is held by Labor's Nick Champion on a 12 per cent margin, but Liberals have grown in confidence during the campaign as internal polling shows the gap rapidly narrowing.