Tony Abbott has said the Coalition intends to "have a crack" at implementing its Direct Action climate policy, rather than model whether it will work, and claims the departments of treasury and finance considered the policy in 2010 and it had emerged "bulletproof".

In fact the "blue book" prepared by the treasury in the event of a Coalition victory in 2010 described a carbon-pricing mechanism as "the only realistic way of achieving the deep cuts in emissions that are required".

It went on: ''A market mechanism can achieve the necessary abatement at a cost per tonne of emissions that is far lower than alternative direct-action policies. Moreover, many direct action measures cannot be scaled up, and, for those that can, the cost per tonne of abatement would rise rapidly, imposing further costs on taxpayers and consumers. All of this serves to underscore the conclusion that the sooner an emissions trading scheme can be implemented the better.

"Too much time has already been wasted, for which the Australian community will necessarily pay a high price."

Two independent modelling exercises conducted recently found Direct Action allocated far too little money to its proposed "reverse auctions" for greenhouse gas abatement to achieve even Australia's minimum commitment of a 5% reduction in emissions by 2020 compared with 2000 levels.

Modelling by Reputex climate analytics, commissioned by the environment group WWF-Australia, found that the money set aside by the Coalition to buy abatement was likely to fall short by $5.9bn a year between 2015 and 2020, or between $20bn and $35bn in total.

Modelling by Sinclair Knight Merz/MMA and Monash University's Centre of Policy Studies, commissioned by the Climate Institute, which used assumptions more generous to the Coalition, found the Coalition would have to find at least another $4bn for its climate policy, or break its pledge to cut emissions by 5% by 2020 and instead allow them to increase by 9%.

But asked on the ABC radio's AM program whether he intended to do his own modelling of Direct Action before implementing it, Abbott said: "Well, we'll get cracking, because we are confident that the results, not the modelling so much, we're more interested in results than modelling, we're confident that the results will show that our emissions are on track to reduce by 5%.

"You don't need modelling to tell you that moving to smarter technology is good for the economy and better soil is good for agricultural productivity … direct action of the sorts that we envisage in our policy is good for the economy and for the environment," Abbott said.

Abbott has previously said that he believes Direct Action will meet Australia's targets, but if it does not, no more money will be allocated.