A lawyer acting for Mr David Trimble said today the High Court in Belfast had been wrong to rule that his ban on Sinn Féin members attending North-South meetings was illegal.
Mr Trimble is appealing the decision of a judicial review in January that the ban he introduced in November to force the progress on IRA decommissioningwas unlawful.
Mr Declan Morgan QC told the court of appeal in Belfast Mr Justice Kerr had misinterpreted the scope of the First Minister's discretion in nominating ministers to the North-South Ministerial Council.
Mr Trimble's lawyer argued the judge had been wrong in law to find that the first minister had "bolted on" the issue of decommissioning to the Ministers' attendance conditions.
Mr Morgan told the appeal court that under the Northern Ireland Act 1998 the First Minister and Deputy First Ministers were obliged to act jointly in nominating but added there was no mandatory requirement for them to agree on who should be nominated.
He said that Mr Justice Kerr in his ruling had found it was legitimate for Mr Trimble to take into account whether a particular minister was honouring the terms of the agreement in relation to decommissioning.
The case was brought by Sinn Féin ministers Ms Bairbre de Brún and Mr Martin McGuinness who had been excluded from meetings since November.
Mr Trimble has refused to lift his sanctions, claiming January's judgment allowed him to withhold nomination of ministers he deemed to be unsuitable.
PA