The DUP has said Ian Paisley was not speaking on behalf of the party after the MP argued the Windsor Framework does not meet their seven tests.
It comes after a report from a unionist think tank which Mr Paisley chairs rejected the UK and European Union's new deal on Brexit's Northern Ireland Protocol.
The Centre for the Union paper, co-authored by loyalist activist Jamie Bryson, said the agreement offers "no sound basis" for the DUP ending its Stormont boycott over the Irish Sea trading arrangements.