The chairman of Plaid Cymru has accused some party members of "plotting" to overthrow the leadership.
Lord Elis-Thomas has criticised the party in recent years
John Dixon spoke after plans emerged to return former president and current assembly Presiding Officer Dafydd Elis-Thomas to the top of the party.
But Mr Dixon said it was "completely unacceptable for small groups of members to be plotting to overturn the democratic choice of the party".
Lord Elis-Thomas, who was president from 1984-91, declined to comment.
The new speculation about Plaid comes the day before the party's annual conference begins in Aberystwyth and follows poor performances in recent elections.
There has been much attention on the party leadership. After the party fell from 17 to 12 seats at the 2003 assembly election, it split the role of the president - Gwynedd Councillor Dafydd Iwan became president and Ieuan Wyn Jones became leader of the assembly group.
Plaid president Dafydd Iwan and assembly leader Ieuan Wyn Jones
But Plaid sources have told BBC Wales they feel change is needed.
This would see Lord Elis-Thomas - Meirionnydd Nant Conwy AM - return to front-line politics as both president and assembly leader.
Possible obstacles to this include the fact the 60-year-old is a controversial figure who has criticised the party in recent years and has had less of a party political role than other AMs.
'Idle and pointless speculation'
But many party members have told the BBC they feel something drastic is needed to save Plaid from decline.
Mr Dixon dismissed this as "idle and pointless speculation" and warned that Plaid needed to be more "disciplined".
"It is completely unacceptable for small groups of members to be plotting to overturn the democratic choice of the party," he said.
"It is a wholly unnecessary diversion from the work that the party needs to do in presenting a clear and consistent message to the people of Wales."
Mr Jones, the AM for Anglesey, said speculation had to stop because it was "immensely damaging," and "affecting the morale of our ordinary party members."
How the Western Mail covered the peer's possible return
Lord Elis-Thomas said he would not comment, and his only intention was to carry on as presiding officer as long as he was supported by fellow AMs.
The latest speculation has flared the day after it emerged that another former party president, Dafydd Wigley, has been nominated as honorary president.
That is expected to be approved at the Aberystwyth conference, which runs from Thursday to Sunday.