The Sinn Féin leader has raised the spending of public money during Leaders' Questions and accused the Government of throwing away millions of euro.
Mary Lou McDonald said that no one was ever held to account for the Leinster House bike shed because €100,000 is now set to be spent on another bike shelter at the National Maternity Hospital.
"It is bike shed groundhog day.......scandalous money on a bike shed again, " Ms McDonald told the Dáil.
She asked Taoiseach Micheál Martin if €100,000 represents value for money for the taxpayer.
The Taoiseach said it is a matter for the National Transport Authority to allocate money for active travel.
But he believes bike sheds should not cost €100,000 and while these structures are needed they should be built "modestly".
Read more: Sinn Féin calls for €100k National Maternity Hospital bike shed tender to be scrapped
"Are we saying workers should not have facilities in an active travel context?" he said.
Mr Martin accused the opposition of wanting two bike sheds built in Leinster House last year.
Ms McDonald rejected the answer and criticised the Taoiseach telling him "don't be smart with me".
She described the Taoiseach as someone who is not good at managing small money adding that he was even worse with larger amounts.
There was also an exchange between the Mr Martin and Sinn Féin Deputy Pearse Doherty, who Mr Martin asked to "go away and design a bike shed for us" before going on to say "cop yourself on Pearse".
Call for means test for carers to be abolished
Meanwhile, Social Democrats leader Holly Cairns has called for the means test for carers to be abolished in next week's Budget.
Speaking during Leaders' Questions, she said carers have been to left to fill the gaps in a broken system and fight endless battles for any small scrap of State support.
Ms Cairns said in no other line of work are people assessed on their partner's income or household savings.
"Carers are treated very differently. Despite being the backbone of the care system in this country and saving the State more than €20bn a year, carers asked to jump through endless hoops to secure a small allowance," she told the Dáil.
She said the removal of the means test is both affordable and achievable.
She asked the Taoiseach if the Government would support a Social Democrats' motion tomorrow on removing the means test.
Mr Martin said there was a commitment to remove the means test in the Programme for Government.
He said there has been progress made, with around 100,000 people receiving the carer's allowance, with numbers increasing every year.
Read more: 'No decisions' made over carers allowance in Budget - Donohoe
The Taoiseach said the Government was proposing to "phase-in" the removal of the means test, and that broader progress would be made on income support.
"In the Budget, there will be a series of measures in respect of carers, carer's benefit is being extended, and the minister for social protection will be bringing proposals to Government in context of the Budget specifically on carers," he said.
Ms Cairns said the question remained - "why wait to abolish the means test?"
"These incremental reforms that you're talking about, these piecemeal things are bureaucratic and carers deserve better. They deserve fair pay and dignity now, yesterday and years ago.
"Government can do this now, but it's still being denied to them," she said.
Mr Martin said it came down to what overall figure is allocated to social protection.
He said if one category is increased, another category may not be, meaning the removal of the means test would be done incrementally.
