Treasury on Tuesday made plain that the new R20-billion lifeline to Eskom to keep its build programme on track still has to be approved as part of the budget process.

Treasury spokesperson Jabulani Sikhakhane reacted after a statement by Energy Minister Dipuo Peters added to confusion about the nature and the source of the additional funding.

Peters told the National Assembly that it was not, as announced last week, an equity injection, but part of the government's extended guarantee framework for the cash-strapped utility.

"It is not additional funding... but it is a R20-billion guarantee from government to allow us, Eskom, to raise loans from the market. It will allow for the building of the Kusile power plant, and therefore be able to secure the security of supply of electricity to South African industry and households," she said.

Peters was responding to a member statement by Democratic Alliance (DA) Parliamentary leader Athol Trollip, who told Members of Parliament (MPs) that the proposed lifeline was unwise, and that the manner in which it was approved, suspect.

Sikhakhane said that he was "not sure" what Peters was talking about.

He reiterated "the proposed equity injection has still to go through the normal budgetary process, including the submission of the funding request to the minister's committee on the budget that makes recommendations to the Cabinet".

"It has not been approved," he said, adding that the final word on the matter would only come in late February when Finance Minister Pravin Gordhan delivers his second budget since taking over as Treasury chief.

"Once approved by Cabinet, provision for allocation of the R20-billion will be made and announced in the budget in February."

Gordhan on Monday side stepped questions about the equity injection, which was announced a fortnight after his medium term budget policy statement, in which he made no mention of it.

He told a media briefing he was not present at the Cabinet meeting where the funding was discussed last week, as he was attending the G20 summit in Seoul.

This added to speculation about the fraught announcement last week that the cash injection had been approved as part of the hybrid funding plan for Eskom to help it complete Kusile.

The electricity supplier was seeking further state funding after announcing in May it faced a funding shortfall of some R190-billion over seven years. The lifeline was announced as a fact by the government communications service last week.

Government spokesperson Themba Maseko initially told reporters that it would be funded by selling non-core state assets. He then back-tracked, saying that the money would be found as part of the ordinary budget process as the sell-off had not been approved by ministers.

Trollip said this showed ministers were divided about the decision to dig into the coffers to help Eskom overcome a funding shortfall of R190-billion over seven years on its infrastructure expansion programme.

"The Cabinet's vacillation on the source of this funding indicates the deep divisions in the executive," he said.

Sikhakhane suggested the media had misread Cabinet's statement on the matter. It said Cabinet had "noted and supported" a hybrid funding model for Eskom, consisting of doubling state guarantees to the utility "and an equity injection of R20-billion over three years starting in the 2011/2012 financial year".

The Treasury spokesperson could not comment on whether consideration would still be given to selling off state assets to fund the lifeline.

Peters on Tuesday also took aim at criticism of the involvement of Chancellor House, the ANC's investment arm, in deals linked to electricity infrastructure.

She accused critics of sounding like a stuck record, and said Chancellor House was an independent entity that could deal with whom it chooses.