The leaders of the Young Greens and Queer Greens have resigned from their positions and left the party claiming they have been left "dismayed" by the party's decisions in government.
In the latest blow to the Green Party, chair of the Queen Greens Tiernan Mason and chair of the Young Greens Tara Gilsenan wrote to elected representatives outlining the reasons for their resignations.
They claimed they were "bullied and harassed" by members and elected representatives in the party.
They published the letter on social media, which says they have resigned with immediate effect.
"We had hoped that we could fight to make a difference and to hold the Green Party to account, but in our short time as chairpersons, we have realised that our efforts have been in vain and that the concerns we have raised have been going unheeded.
"To that end, we feel that we are no longer able to represent these affiliate groups of the Green Party.
"While we understand the constraints that come with being the smallest party in a coalition, we have found ourselves dismayed to see our elected representatives vote against party policy, even outside the constraints of the Programme for Government, again and again."
The pair said they fought against the party voting for evictions during the Covid-19 pandemic, and against the sealing of the mother and baby home documents, as well as a "lacklustre" Climate Bill.
"We have not been successful," they added.
"We have been overlooked, left out, ignored, bullied and harassed by members and elected representatives of the party. Seeing as we are unable to make a difference we sought to, we are resigning with immediate effect.
"We would suggest to the remaining officials in the party hierarchy that you need to remember who put you where you are - those who voted for people and planet are outraged at your action."
They signed off the letter warning that history will "not be kind" to the party as it stands.
Earlier this week the Dáil passed legislation which allows a database created by the Commission of Investigation into Mother and Baby Homes to be sealed for 30 years.
The Dail passed the Bill by 78 votes to 67 on Thursday night.
The Green Party has been dealt a number of blows in recent months following its decision to enter a coalition with Fianna Fáil and Fine Gael.
High-profile party member Saoirse McHugh and a number of others left, including the former chair of Queer Greens, citing disillusionment with the party for entering government with the two parties.
The Green Party has been contacted for comment.