SDLP infrastructure minister Nichola Mallon last night hit out at the cancellation of another North South Ministerial Council (NSMC) meeting following a DUP no-show.
Ms Mallon called for "urgent intervention" from the UK and Irish governments following the latest snubbing from a DUP minister.
It comes after Agriculture Minister Edwin Poots did not attend another NSMC meeting on Wednesday amid a DUP boycott over its opposition to the NI Protocol.
Mr Poots said he did not attend as he was following party policy laid down by Sir Jeffrey Donaldson who has instructed his ministers to boycott north-south meetings, among other measures.
The NSMC is the main body for cross-border co-operation between Stormont and the Irish government.
Ms Mallon has previously criticised the DUP for its boycotts, claiming the party had "deliberately obstructed" the work of the meetings.
Speaking after the latest DUP no-show, Ms Mallon said it was a "gravely serious" situation.
"Ministers have a responsibility under their ministerial code," she told the Belfast Telegraph.
"We also have a responsibility to uphold all elements of the Good Friday Agreement, so I have written to both the British and Irish governments, as co-guarantors of the Good Friday Agreement, to ask for their urgent intervention, because the SDLP wants to see stability in these institutions.
"We want to see us deliver for our farmers, for our businesses - boycotting north-south institutions doesn't achieve any of that.
"The DUP have a problem with Brexit, which they created and they own, their problem is with the British government - not north-south institutions, not with collaboration to support our farmers, not with tackling the climate emergency."
