Both of Stormont's Green MLAs have rejected a draft programme for government in the Republic that the party has signed up to.
Clare Bailey, its leader in Northern Ireland, and North Down MLA Rachel Woods have now confirmed they will vote against the blueprint agreed with Fine Gael and Fianna Fail last week.
Green Party leader Eamon Ryan has rejected Ms Bailey's call for him to renegotiate the draft deal.
Ms Woods is the latest party representative to speak out, alongside TDs Francis Duffy, Patrick Costello and Neasa Hourigan, as well as Dublin City councillor and party chair Hazel Chu.
Ms Woods said yesterday: "I believe that we can build back better from Covid-19.
"I also believe that a better deal is possible, one that will bring positive change and a just transition to a fairer society and low carbon economy.
"That's why I'm voting no to this programme for government."
Ms Bailey had originally abstained from a vote among the Green parliamentary team last week, but has now added her name to a statement opposing the chance to enter a coalition.
The statement reads: "As Green Party elected representatives and members from across this island, we believe that this draft programme for government represents an unjust recovery. That's why we will vote no on this draft programme for government.
"This offer of government represents one of the most fiscally conservative arrangements in a generation.
"Regressive taxation in the form of carbon and sugar taxes are included, while corporation tax and the top rate of income tax remain unchanged.
"It's a deal that was negotiated in good faith but fails to deliver on our promise to tackle homelessness and provide better healthcare. It sets out an inadequate and vague pathway towards climate action.
"A better deal is possible - voting no on this programme for government is a step towards securing that better deal.
"Transformative change was called for by the electorate earlier this year. That call must be answered by not only the Green Party, but every party that promised positive change."
Writing in this paper, Ms Bailey said the deal did not deliver "a just transition to a fairer society and a low carbon economy" and called for parties that had promised change earlier this year "to step up and deliver".
Belfast councillors Anthony Flynn and Brian Smyth also voiced their opposition.
Mr Flynn said: "I spoke about the lack of action on tackling cruel and inhumane greyhound industry in RoI as well as hare coursing and other animal welfare issues, Brexit and austerity.
"I cannot support an unjust transition, we can do better."
Mr Smyth added: "Climate justice and social justice are one. As a qualified youth worker I can't support something that reduces the opportunity of young people. Green politics should be that hand reaching into the darkness to bring those up into the light and to deliver a fairer society."
Of the three possible coalition partners, the Greens require the biggest endorsement from their membership to proceed.
At least two-thirds of members registered to vote must back the deal ahead of next Friday.
Here, only 195 out of an estimated 650 party members have registered to vote.
Mr Ryan said he believed it was possible to address the climate and biodiversity crisis in government, while also addressing issues such as housing and health.
He admitted the deal was not perfect, but he said it was important to get the best deal for the country and not just for the party.
Mr Ryan also warned uncertainty would follow if the coalition deal was not passed.