The DUP MLA Jonathan Bell has been suspended from his party, following claims about the controversial "cash for ash" funding.
He said he was put under pressure by DUP officials to delay cancelling the renewable heating scheme.
The fuel grant was set up when Northern First Minister Arlene Foster was Minister for Enterprise.
The scheme paid users more than the cost of their fuel, and will end up costing the north's exchequer over half a billion euro.
That has led to calls from Sinn Féin for Ms Foster to resign.
Tomorrow, the Stormont Assembly will discuss a vote of no confidence in the First Minister.