SIR Jeffrey Donaldson been called on to explain why he took almost three weeks to retract unfounded claims about the protocol delaying treatment of cardiac patients.
Sinn Féin's Colm Gildernew said there was an "onus" on the DUP leader to say "why he did not act sooner to correct the record".
It has emerged that Sir Jeffrey received a letter from a health trust boss dismissing the allegations almost three weeks before he publicly withdrew his remarks.
A trail of correspondence released under Freedom of Information also suggests Sir Jeffrey did not raise his allegations with either the Belfast or Southern Trust before going public with the claims.
The DUP leader was last month forced into an embarrassing climbdown after the two health trusts dismissed his claim that cardiac patients in a Belfast hospital had to wait three weeks for surgery because the protocol meant equipment had to be sourced from outside the UK.
Both the Belfast and Southern trusts, as well as the equipment supplier, dismissed the suggestion that the disruption was a result of the post-Brexit trading arrangements.
Emails show the Belfast trust drafted a statement on October 28 just hours after Sir Jeffrey's on-air claims.
The correspondence, obtained by Belfast Live, also shows Department of Health officials voicing concern that the DUP would use the issue for "electioneering purposes".
Sir Jeffrey later expressed regret that he had placed inaccurate information in the public domain.
Mr Gildernew said: "Misinformation on an issue as sensitive as the treatment of cardiac patients should not have been left in the public domain for three weeks."
