A Brookfield Asset Management-led consortium is seeking fresh talks with Origin Energy's top investor in a last ditch effort to rescue its A$19.4-billion takeover plan for the Australian utility.

Brookfield wants to reopen dialog with AustralianSuper to win over the giant pension fund after a sweetened bid was rebuffed on Thursday, people familiar with the matter said. There is no guarantee the talks will happen, said the people, who asked not to be identified as they were not authorised to speak publicly.

Representatives for Brookfield and AustralianSuper declined to comment.

Among the options that could be considered in the discussion would be joining forces, one of the people said. However, should the current gambit falter, Brookfield can press ahead with its plans even without AustralianSuper’s explicit support, by increasing its shareholding and using a different takeover structure, another person said.

This week’s rejection is the latest Australian setback for Brookfield, which for over a year has been trying to invest in local energy firms that must decarbonize but lack capital to do so. Brookfield launched its bid to acquire Origin after an earlier offer with technology billionaire Mike Cannon-Brookes to acquire AGL Energy, another utility, was turned down.

The Canadian giant is not alone. Foreign firms eager to bet on Australia’s role in the energy transition have struggled of late, with domestic funds and high-profile local investors contesting takeovers. Iron-ore tycoon Gina Rinehart has waded into lithium deals, and her purchase of shares in miner Liontown Resources ultimately scuppered a takeover bid by US giant Albermarle last month. She has now built up a stake in Azure Minerals, which has backed an offer from Chilean lithium giant SQM.

The Brookfield group, which includes EIG Global Energy Partners, had attempted to bring the Origin transaction to a head on Thursday by raising its “best and final” offer by about A$1.2-billion.

But AustralianSuper — the country’s largest pension fund and the company’s largest shareholder — swiftly deemed it “substantially below our estimate of Origin’s long-term value,” citing the target’s green ambitions as a compelling reason for a higher price.

Under the current proposal, Brookfield would acquire Origin’s power generation and electricity retailing business, which serves more than 4.5-million homes and businesses, and currently operates Australia’s biggest coal plant. EIG would take Origin’s liquefied natural gas unit, one of Asia’s largest. Saudi Aramco recently bought a stake in EIG’s MidOcean Energy to gain exposure to Australian LNG.

AustralianSuper raised its stake in Origin on Friday after the rejection, and now holds about 15% of the utility’s shares, enough to potentially block an acquisition. A Nov. 23 investor meeting will require three-quarters of votes cast to back Brookfield’s proposal in order for the deal to go ahead.