Election 2015: Labour and Plaid clash in TV debate
Labour and Plaid Cymru have clashed on whether the two parties could work together if next week's election results in a hung parliament.
During BBC Wales' televised leaders debate Labour's Owen Smith challenged Plaid leader Leanne Wood over whether she would "let a Tory government in by the back door".
But she responded that Labour's "time was up on taking people for granted".
On Friday Ed Miliband had ruled out doing a deal with Plaid.
Ms Wood has said she could do a deal to put Labour in power even if the Plaid's sister party the SNP was not involved.
Appearing to concede that Labour may not win a majority, Mr Smith said: "The question is for Leanne - in the event of Labour being the largest party, and Labour forming a government, perhaps a minority government, would Leanne vote down our programme for getting rid of the bedroom tax, for increasing the minimum wage - would you, Leanne, let a Tory government in by the back door?"
She responded: "I just love the way that you take for granted the way you think Plaid Cymru votes are going to go, just in the same way you have taken for granted the people of Wales over many many decades.
"I think the time is up on taking people for granted, Owen Smith."
Welsh Secretary Stephen Crabb said a vote for a Conservative administration was the alternative to what he dubbed a "squabbling coalition of chaos".
The debate also heard from the Welsh Liberal Democrat's Kirsty Williams, UKIP Wales' Nathan Gill and the Wales Green Party's Pippa Bartolotti, as all six politicians took part in the final Welsh televised debate.
Ms Williams faced questioning over the Lib-Dem coalition role on benefit issues and told the audience:" There have been tough decisions about welfare."
The Green's leader highlighted what she described as the "disproportionate" burden being felt by women under austerity measures, while UKIP's Welsh leader hit on the devolved issue of the NHS - warning that Labour had made "a right pig's ear" of the health service in Wales.
Analysis: Nick Servini, BBC Wales political editor
Large chunks of last night's debate at the Sherman Theatre in Cardiff were dominated by the coalition government's welfare reform policies.
The Conservative Welsh Secretary Stephen Crabb came under sustained attack on the subject, including from his party's former coalition partner, the Liberal Democrats.
But the Welsh Lib Dem leader Kirsty Williams had an uncomfortable moment of her own as well in a question about her party's role in cutting back the UK's welfare bill.
She wasn't alone as Labour's Owen Smith faced some difficult questions over the Labour Welsh government's record running the NHS.
While UKIP focused on financial responsibility, and a more efficient use of foreign aid, the Greens pushed their message on greater financial protection for women and more protection for the environment.
But arguably the most lively exchange came towards the end of the debate when Labour and Plaid clashed over a potential working relationship in a hung parliament.
This was the final set-piece televised debate in the general election campaign in Wales. What's called the air war has come to an end and the ground war will now get fully underway as the political parties look to get their vote out on polling day.