Media playback is unsupported on your device Media caption Chris Bryant says Plaid Cymru supporters joining Labour cannot vote for the leader

Plaid Cymru supporters are joining the Labour party to vote for left-winger Jeremy Corbyn as leader, an MP claims.

Rhondda MP Chris Bryant has been involved in a row on social media over one new member's true affiliation.

Esther Nagle claimed the MP breached her privacy, but admitted she still supported Plaid Cymru.

Mr Bryant, who backs Yvette Cooper, said only genuine Labour supporters would be allowed to take part in the leadership election.

Andy Burnham and Liz Kendall are also contenders alongside Ms Cooper and Mr Corbyn.

'Worrying'

Some Labour figures have called for the leadership election to be suspended, amid claims supporters of other parties have registered as Labour members in order to take part.

Image copyright Jeff Overs/BBC Image caption Yvette Cooper, Jeremy Corbyn, Liz Kendall and Andy Burnham hope to succeed Ed Miliband

Speaking on the BBC's Newsnight programme, Mr Bryant said it was "brilliant" so many people wanted to vote in the leadership contest, but some aspects were "worrying".

"We've come up in my own constituency in the last few days with two people who are passionate supporters of Plaid Cymru but they're down as registered voters in this election," he said.

"They will not now be allowed to vote."

Ms Nagle, who stood as a Plaid Cymru candidate in local council elections in 2012, said she was "appalled" Mr Bryant had discussed her decision to join Labour on social media, claiming it was "an infringement of my right to privacy".

She added: "I am no longer a member of Plaid Cymru, having allowed my membership to lapse some time ago, although I still very much support Plaid Cymru."

A Plaid Cymru spokesperson said: "We are not aware of any current Plaid Cymru members joining Labour in order to vote in the leadership election.

"Any member who joins a party which stands against Plaid Cymru in elections would immediately be expelled from the party.

"The Labour leadership election is an internal matter for the Labour Party."

Clwyd South Labour MP Susan Elan Jones claimed "around a dozen" new applicants who joined her constituency were connected with other parties.

"There is an idealism about the new process and it is open to abuse," she said, calling for a six-month waiting period before new members could take part in leadership votes.