Sinn Féin deputy leader Mary Lou McDonald described Tánaiste Joan Burton as a “wimp’’ after claiming she failed to say if she supported the deduction of unpaid water charges from people’s wages or social welfare payments.

Amid heated Dáil exchanges on Thursday, Ms McDonald insisted that Ms Burton was not answering the question.

“I wish the Tánaiste to answer ‘yes’ or ‘no’,’’ said Ms McDonald. “Do you support the plan for attachment orders….?’’

The reply from Ms Burton, who was seated, was inaudible.

“You’re a wimp,’’ said Ms McDonald.

Earlier, Ms McDonald said it seemed Labour was to become Irish Water's debt collector, "sticking your hand into the pockets of families who are struggling to provide for their children or to pay their mortgage or rent''.

She asked if that was the way Labour helped cash-strapped families.

Ms McDonald asked the Tánaiste if she supported Minister for the Environment Alan Kelly’s proposal “to raid people’s wages, social welfare and pensions’’.

Ms Burton said she supported Mr Kelly’s work “in actually bringing a proper investment plan and structure for water development in this country’’.