Origin said it will adjourn Thursday's scheme meeting until December 4 to consider the new offer.
Based on proxy votes received to date, it was unlikely that the previous offer would have achieved the required 75 per cent approval by shareholders, Origin said.
Origin's largest shareholder, AustralianSuper, has opposed the $16 billion deal, saying it undervalued the company.
The new offer would allow institutional shareholders the right to reinvest into Brookfield-owned Energy Markets business but is otherwise at the same terms, about $A9.43 per share, partially paid in US dollars.
In the event the scheme isn't approved, the new offer has the option for an alternative transaction that would consist of Origin selling its energy markets business to Brookfield for $12.3 billion, and EIG making an off-market takeover offer for its LNG business.
Shareholders would only receive $9.08 per share under this alternative offer, but it would only need the acceptance of 50.1 per cent of shareholders
"The board notes that the transaction appears inferior to the existing scheme," Origin said.
"The board has significant reservations as to the complexity, conditionality and differing value, and potential adverse tax outcomes to Origin and shareholders," it said.