The Alliance Party leader and Justice Minister Naomi Long has said uncertainty remains over whether new legislation on the protocol can end the Stormont impasse.
She made the comments on BBC Good Morning Ulster before the government is expected to introduce the legislation this afternoon.
Speaking on BBC Good Morning Ulster, Ms Long said the DUP had been the only Northern Ireland party consulted over the latest move.
"There’s a lot of uncertainty around this legislation, not least the legal uncertainty,” she said, addressing concerns it will not be within international law.
Speaking to the BBC on Sunday, the Northern Ireland Secretary Brandon Lewis insisted the legislation would be legally sound.
The Irish Foreign Affairs Minister Simon Coveney, however, said suggestions that the UK was planning to break international law would represent a new low for Anglo-Irish relations.
Ms Long was asked if the new legislation was worth doing if it was legal, brought the DUP back to Stormont and reopened trade negotiations with the EU.
"First of all, Brandon Lewis is pretty bullish on everything but it doesn’t necessarily mean he’s correct,” she said.
"And listening to the legal experts, it’s hard to see how any unilateral action by one state can override an international treaty by two states.
“It will be interesting to see how the government try to spin this to say this is within international law.”
She added that the easiest way to resolve tensions around the protocol was to build trust with the European Union.
"Because what we’re asking the European Union to do is to devolve to the UK responsibility for protection of the single market.
"They’ll only do that if they trust us to do the job right.”
She said repeated threats of taking unilateral action over the protocol was having the opposite effect.
Ms Long said another worry was that criminal gangs and smugglers could begin to take advantage of any uncertainty over trade regulations.