The DUP MLA Jonathan Bell has been suspended from the party following comments made about First Minister Arlene Foster in a row over the Renewable Heat Incentive scheme crisis.
Mr Bell was heavily critical of his party leader in her handling of a whistleblower flagging up that the botched scheme was being abused.
It has been projected that the initiative could end up costing the taxpayer as much as £400m.
A DUP spokesperson confirmed that party officers met on Saturday and that the Strangford MLA’s suspension had been unanimously agreed.
The Assembly has been recalled on Monday to discuss a potential vote of no confidence in the First Minister.
Deputy First Minister Martin McGuinness joined calls for Mrs Foster to step aside while an investigation is carried out, a call that the DUP leader has rejected.