The European Commission proposal, known as backloading, would remove permits from the first three years of the new phase of the carbon market (2013-2015) and put them back on the market at the end of it (2019-2020).
Coal-dependent Poland strongly opposes price-raising moves on the EU's Emissions Trading Scheme (ETS), where a surplus generated mostly by recession has plunged the price to less than €6 per tonne, compared with around €30 in 2008.
But the backloading plan, which many say is urgently needed to restore faith in the ETS, can still pass, Hedegaard said.
"Yes, if the Germans back it. And then I hope the UK would also come out in favour of that because obviously they have said they want to be even more ambitious, but in politics sometimes you have to take what you can get when you can get it," Hedegaard said in an interview with Reuters.
"If that changes after the elections in Germany, yes then I think we will get them," she said at the World Future Energy Summit in Abu Dhabi.
Germany, the EU's most influential member, has yet to take a stance.
The environment minister has spoken in favour of the plan, while the economy minister, reflecting the powerful heavy industry lobby opposed to any increase in energy costs, has so far opposed it.
German elections in Lower Saxony on Sunday could lead to a change of economy minister and unlock the indecision.
Elections can halt process
Some observers, however, have speculated Germany will slide into an abstention as it focuses on federal elections later in the year, at which Chancellor Angela Merkel will seek another term of office.
Hedegaard called for early decisions.
"I think it is urgent and I think that those member states that haven't internally made up their mind yet must realise that industry and investors need to know what they can count on," she said.
She declined to speculate on the fate of the backloading proposal should Germany refuse to back it.
Ireland, as current holder of the rotating EU presidency, has said it will try to broker a deal before the end of its six months at the helm of EU debate.
A presidency source on Wednesday (16 January) summed up the mood of member states so far as "undecided, with a few exceptions".
The presidency and the Commission meanwhile are working with other trading schemes to develop links, notably with Australia, with which plans for a tie-up were announced last year.
"During the Irish presidency, we will be seeking a mandate that we can start the very formal negotiations," Hedegaard said of the talks with Australia.
"It is just one part of the bigger vision that in the end - not tomorrow, not next year, not in the very foreseeable future - but in the end, the aim should be to have a global price on carbon."