Welsh assembly Deputy Presiding Officer John Marek has accused First Minister Rhodri Morgan of "cronyism" over the appointment of its top legal officer.
Rhodri Morgan's office says he has never met Malcolm Bishop
Dr Marek called on Mr Morgan to admit he was wrong to block the appointment of Gerard Elias QC as counsel general.
Opposition parties have also criticised Mr Morgan over the issue.
But Mr Morgan's office has dismissed the allegations as "absurd".
Dr Marek, who left Labour last year, joined the attack led by the Conservatives and Plaid Cymru.
Mr Elias was recommended for the job by an independent panel, but BBC Wales' Dragon's Eye programme learned that Mr Morgan wanted another QC, Malcolm Bishop, who has Labour connections.
The Welsh Assembly Government and the Civil Service Commission, which oversees the recruitment process, both said the procedure was fair.
Mr Bishop, a former Labour candidate, is also a close associate of former Lord Chancellor Derry Irvine.
But the first minister's office said on Thursday that he did not know, had never met and had never spoken to Mr Bishop.
Dr Marek told Dragon's Eye that he did not believe the assembly's house committee, which has a key role in the way the assembly is run, "would have a crony of Rhodri Morgan's" as the assembly's chief legal adviser.
Dr Marek said the objections Mr Morgan had given for vetoing Mr Elias were not good or reasonable.
He predicted that Winston Roddick, who retired as counsel general in October, may be the first and last person to hold the post because the roles could now be split.
Dr Marek said there could now be a chief legal adviser for the assembly government and a separate one for the assembly's parliamentary side.