Labour's leader at County Hall claims Plaid's top brass are "fighting like two cats in a bag" after a turbulent week which saw Lord Elis-Thomas lose his Assembly committee chairmanship and party portfolio responsibilities after he was critical of leader Leanne Wood’s speech during the party’s spring conference.
Lord Elis-Thomas said in the aftermath of Ms Wood's speech that equating a vote for Ukip as a “vote against Wales” was “facile”.
Ms Wood said she had moved to discipline Lord Elis-Thomas after he “publicly opposed” her position “without raising any concerns in advance”.
Saying he strongly supported Lord Elis-Thomas, Cllr Madge accused the Plaid leader of being "out of touch". He added: "We live in an open society where people hold a lot of different views.
"Plaid seem hell-bent on attacking each other like a couple of cats in a bag. Now they're even attacking their former leader. and people are getting fed up with it.
"I believe that Lord Elis-Thomas should join the Labour party in Cardiff Bay – what has happened this week may persuade him to do so." Were Lord Elis-Thomas to defect, it would give Welsh Labour a majority of one.
Cllr Madge claimed that Plaid's sole MEP, Jill Evans, was "odds-on" to lose her seat at the European elections in May and again claimed the party were "scared stiff" of Calum Higgins, Labour's Parliamentary candidate for Carmarthenshire East and Dinefwr.
"Calum has an excellent chance of winning the seat – one of my great ambitions is to see this seat recaptured by Labour after we lost it in 2001," he said. "What we're hearing from the public suggests to me Plaid are going to lose."
However, MP Jonathan Edwards said he fully supported Ms Wood's assertion that Ukip would never stand up for Welsh interests.
"There's a choice of two futures: the narrow, isolated, little England future of Ukip or our vision of a worldwide-looking, modern Wales," he added.
"Lord Elis-Thomas is a hugely inspirational figure who has made a huge contribution to both the party and Wales over the past 40 years – he would be completely undermining that legacy by joining the Labour party."