The party has withdrawn its ministers in protest over the Northern Ireland protocol.
A boycott of North-South Ministerial meetings by the DUP is unlawful, according to the High Court in Belfast.
The party has withdrawn its ministers from the North South Ministerial Council in protest over the Northern Ireland protocol.
In his judgement Mr Justice Scoffield says "it frustrates, is contrary to and is in breach of legal duties contained in part five of the Northern Ireland Act 1998."
It's after judicial review proceedings were taken by a Belfast man over the lawfulness of the move.
In response to the judgement, the DUP said it's further proof the conditions to trigger article 16 have been met.