Sinn Féin's Brexit spokesman said: “The UK government has clearly intended to violate international law by trying to tear apart the Brexit Withdrawal Agreement and Irish Protocol through Single Market Act.
“Passing this law would not only violate international law, it would also lead a trainer and horses through another internationally binding agreement, the Good Friday Agreement.
“The law would give the UK government the power to unilaterally impose its rules and regulations on the assembly, regardless of the views of the democratically elected MLAs and ministers in the executive branch.
"This is a clear deviation from the Good Friday Agreement and the political institutions it created," emphasizes the local MPA.
“It contains clauses that would give the UK government the power to force the executive and assembly to accept lower environmental, food safety and animal welfare standards, endanger our local agro-food industries and incapacitate the executive.
“It would also create an unelected quango that could challenge the democratically elected decentralized assemblies.
“It would be crucial that this undermines the pan-Irish aspects of the Good Friday Agreement as it completely overrides North-South cooperation.
“This was a key element of the Good Friday Agreement for Nationalists and Republicans and cannot be repealed at will by the UK government.
The Sinn Fein MPA continued: “I have now written to the leaders of the main political parties in Westminster, reporting the major Good Friday Agreement violations resulting from the Internal Market Act.
“It is important that you understand the implications of this proposed law for Northern Ireland, relations in the island of Ireland and relations between these islands.
"The UK government and Parliament must not simply undermine and undermine the Good Friday Agreement and the decades of progress that has resulted from it," he added.