A row has broken out within Plaid Cymru after leader Leanne Wood said she was not ruling out a Welsh Government coalition with Labour after the Brexit vote.
She dismissed a deal after the assembly election but told BBC Wales the referendum "changed everything".
Plaid's Neil McEvoy AM and MP Jonathan Edwards expressed their opposition to working with Labour on Twitter.
AM for South Wales West, Bethan Jenkins, also criticised the comments.
Plaid agreed a limited deal after May's assembly election to allow Welsh Labour leader Carwyn Jones, whose party won 29 of 60 seats in the May election, to be re-installed as first minister.
'Ready to step up'
Asked on Radio Wales' Sunday Supplement programme if she was open to coalition, Ms Wood said: "What happened on Thursday night has changed everything really, so I would not be prepared to close anything down.
"I'm still not looking for ministerial seats per se, but I do think that this situation is serious now.
"We're going to lose a lot of money, there are grave risks to our economy, to some of the jobs we have got here and to some of the funding of key projects we have got here.
"It necessitates leadership - that's what we need in Wales now.
"Strong, confident leadership and my party is ready to step up to the plate and work with whoever in order to provide the leadership Wales now needs."
But in response, South Wales Central AM Neil McEvoy, who was newly elected in May, said on Twitter: "I'm absolutely opposed to propping up a toxic Labour Party.
"No deals, no coalition. Labour is Wales' biggest problem."
Plaid Cymru MP Jonathan Edwards was also critical of any support for Labour while Jeremy Corbyn was facing challenges to his leadership.
He tweeted: "Labour today is defined by chaos, dissent and disunity. Now is the time for @Plaid_Cymru to challenge not endorse them".
Ms Wood's comments were also criticised by Plaid Cymru AM Bethan Jenkins.
"So when were AMs and members consulted on this stance", she tweeted.
Interviewed on Sunday Supplement, Mr Jones said: "We are talking to Plaid Cymru, we have a formal structure in place.
"There are three committees in place so the parties can talk to each other early on about things like the budget, about things like new laws.
"My view has always been that when it comes to having the strongest voice for Wales we are of course looking to work with other parties who are in the same position as we are on in terms of strengthening Wales' position.
"So it's not as if we are refusing to talk to Plaid Cymru - we are talking to Plaid Cymru.
"It was made clear after the election that Plaid at that point weren't interested in anything beyond that kind of structure."