New doubts have emerged about the government's funding model for Irish Water.

It has been claimed in the Dáil tonight that the grant being given to every home may cost up to €35m more than first estimated.

The government says 1.3m households are eligible for the grant - but the CSO says there are 1.65m households in the State.

Richard Boyd-Barrett TD says if the government has got its figures wrong, it must abandon the project entirely.

"If you think that the fiasco, the outrage, surrounding the issue of Irish Water has been bad to date - if you've got this wrong you are in deep, deep trouble," Mr Boyd Barrett said.

The Dáil was adjourned for the night at 10pm and will resume at 10am tomorrow.

There were also angry scenes in the Dáil this evening, with the environment minister accused of telling another TD to "F' off".

Mattie McGrath TD says the comment was directed towards him by Environment Minister Alan Kelly during a debate on water charges this evening.

The minister later said he wasn't aware of the comment, and said if he made it, it was "involuntary".

He has apologised for the remark, if he made it.