Mary Lou McDonald insists carbon taxes are not the solution to tackling climate change.
The Sinn Féin leader believes struggling families will be hit most by any new taxes proposed to tackle the issue.
Taoiseach Leo Varadkar has strongly criticised the opposition party's approach.
However, Deputy McDonald says taxes should not become a mechanism for piling costs on families.
"The ways in which we tackle climate change and we address the issue of carbon emissions has to have reality front and centre, social justice front and centre," said Ms McDonald.
"It should not become a mechanism for piling more punitive costs on families that are just about making it or many of whom aren't making it as things stand."