The Welsh Secretary's vote to keep a no-deal Brexit on the negotiating table was "ludicrous", former Wales Office minister Guto Bebb has said.
MPs on Wednesday night voted to reject leaving the European Union without a deal.
Alun Cairns followed the government whip in opposing the move.
Tory MP Mr Bebb said a no-deal Brexit damages Wales more than other parts of the UK. The Conservative Party was asked for comment.
Wednesday night saw the House of Commons descend into confusion as MPs voted on whether they were opposed to leaving the EU without a deal.
The government had tabled a motion ruling out a no-deal outcome, but only on 29 March - the current exit date.
Some MPs wanted it ruled out in all circumstances and successfully passed an amendment 312-308.
Because of Commons procedure it had to be voted on again. The changes led the Conservatives to whip against the final motion, but MPs passed it 321 votes to 278.
Six of the eight Welsh Tory MPs voted against the no-deal motion - Chris Davies, David Davies, Glyn Davies, Simon Hart, and David Jones as well as Alun Cairns.
Aberconwy MP Guto Bebb voted for it, and Stephen Crabb abstained - alongside thirteen government ministers.
Alun Cairns went on to abstain on Thursday's vote calling for a delay to Brexit, by voting both for and against it.
"It's disgraceful that some members from Wales voted for leaving without a deal," said Mr Bebb.
"I can't understand the logic of those who represent rural constituencies who are prepared to put the agricultural industry in danger as they have done."
Asked if it was responsible for Mr Cairns to vote to keep no-deal on the table, Mr Bebb said: "No, I don't think it was.
"Alun is a good friend of mine but I think that vote was a mistake on his behalf.
"We all know that a no-deal Brexit damages Wales more than most parts of the United Kingdom.
"I think the decision to keep no-deal on the table is actually ludicrous because, let's be honest, when we say that keeping no deal on the table is a bargaining chip, it's simply not the case."