Scott Morrison has attempted to back away from his previous voluble support for the national energy guarantee by suggesting the Neg is not a Coalition measure if it has an emissions reduction target of 45%.

The prime minister was asked by Labor in question time on Wednesday whether he agreed with his own previous assessments that the Neg achieved lower electricity prices.

Morrison attempted to reposition, saying there was a “misrepresentation” from Labor about the Neg being a Coalition measure because the government had never proposed a 45% emissions reduction target.

“In the proposal considered by the government, the emissions reduction target was 26% – it wasn’t 45%,” Morrison told parliament. “The Labor party cannot use the national energy guarantee as some sort of trojan horse to legislate a 45% emissions reduction target, Mr Speaker.”

Morrison said Labor was engaged in a “tricky and shifty lie”.

Malcolm Turnbull and the then energy minister Josh Frydenberg developed the national energy guarantee, and it was sold enthusiastically by other members of the government, including Morrison, then treasurer.

The mechanism was to have an emissions reduction target for electricity of 26%, but officials from the Energy Security Board made clear on a number of occasions that a core feature of the policy was the scaleability of the emissions reduction target, including in their final design advice to governments on the scheme.

“The guarantee mechanism ensures the electricity sector contributes its share towards Australia’s Paris emissions reduction commitments, and importantly, can accommodate different levels of emissions ambition overtime,” the chair of the ESB, Kerry Schott, said in August.

“It is possible that higher emissions reduction targets may be set in the future by the Australian government,” the advice noted. “In this case, the guarantee mechanism and framework will automatically accommodate the new targets.”

As well as the consistent advice that the target was scaleable, Frydenberg also agreed to review the 26% target after five years as part of his negotiations with the states, stepping back from an ambit claim that it be locked in for a decade.

Turnbull dumped the emissions reduction component of the Neg in late August in an attempt to stave off a conservative-led push against his leadership, and Morrison formally dumped the emissions component with a cabinet decision shortly after he became prime minister.

The government’s decision to abandon the Neg framework has been widely criticised by stakeholders who view the mechanism as the only viable option for settling the decade-long climate and energy policy wars.

This week, former deputy Liberal leader Julie Bishop called for the revival of the Neg. She said the government needed to consider energy policy “through the prism of securing bipartisan agreement with Labor, to establish a long-term, stable regulatory framework that will support private-sector investment in generating capacity”.

“The generators need long-term certainty to give them confidence to make large-scale capital investments that will provide affordable and reliable energy, and with an appropriate level of return,” Bishop said.

Labor has attempted to resuscitate the Neg, which continues to enjoy wide support from the energy and business sectors.

Bill Shorten unveiled the opposition’s energy policy reboot last Thursday, repeating an invitation for the Coalition to embrace the mechanism it ditched during the August leadership implosion, but also outlining a detailed alternative in the event the pitch for bipartisanship is ultimately rebuffed.

Labor has been clear for months that if it wins the next federal election, and pursues the Neg, the target would be more ambitious than the government’s, because the advice was a 26% reduction would be met over the first two years of the scheme.