The SDLP leader made the claim while calling on the British Prime Minister Boris Johnson to fast-track Stormont sustainability legislation at Westminster this afternoon.
"Health waiting lists are through the roof in Northern Ireland. Hard-pressed families are being hit by decisions from this government. But the DUP has been hit by a bad opinion poll so they are threatening to bring down the very institutions of the Good Friday Agreement.
"Will this Prime Minister commit today to fast-tracking the legislation going through this house, agreed at New Decade, New Approach (NDNA), to stop the institutions coming down if one political party has a petulant strop?" he asked.
Mr. Johnson replied: "I agree with him it is very important the institutions of Northern Ireland should be robust and they should continue but I would also think that a responsible government has to address the issues of the Protocol, the lop-sidedness and the way in which they EU has chosen to interpret [it] that I do not believe satisfies the Belfast/Good Friday Agreement and that's what we are going to do."