The Orange Order has said the Northern Ireland protocol must be scrapped immediately and it won't allow the local economy "to be reorientated towards Dublin in order to facilitate a united Ireland by stealth".
Its statement came as the DUP's online petition secured the 100,000 signatures needed to secure a parliamentary debate on triggering Article 16.
"Yes, we did it," said Arlene Foster. "That's people power and politics in action together."
The Grand Orange Lodge of Ireland said it had met with all the unionist parties and was encouraged by the "unanimity of purpose shown" in recent days.
It said the protocol must be binned immediately.
"There can be no tweaking around the edges, or kicking this issue down the road in the hope that we learn to live with it - the protocol is fundamentally flawed and must go now," it said.
"Any border in the Irish Sea which requires paperwork or checks of any kind on products destined for use in Northern Ireland is totally unacceptable.
"We will not allow the economy of Northern Ireland to be reorientated towards Dublin in order to facilitate a united Ireland by stealth."
The Grand Lodge said the Protocol must be challenged "through peaceful and sustained political pressure".
It added: "We support the first steps that all unionists parties are taking in applying political pressure and await further sanctions and actions as required.
"We understand that each political party has a different role to play and that they will advocate different tactics on how best to remove the protocol.
"However, each assured Grand Lodge officers that they recognise that this issue is too important to play party politics with."
The Orange Order called on London to vigorously challenge Dublin. "The Republic of Ireland's Foreign Affairs Minister, Simon Coveney has declared, 'The protocol is not going to be scrapped.'
"We call on our Prime Minister Boris Johnson - who has repeatedly reassured us that he is a unionist - to exercise the UK's newly recovered sovereignty by robustly responding on behalf of his fellow unionists in Northern Ireland by evoking Article 16 immediately."
Arlene Foster hailed the success of the online petition.
"Whilst we have reached the 100,000 trigger, I encourage people throughout Northern Ireland and the rest of the UK to keep signing and keep registering support for our campaign to free us from the protocol," she said.
"The people have made a very public appeal to the government of their country to act.
"This is not the time for more words and drawn-out processes. This time for affirmative action to ensure that there is an unfettered flow of goods within the UK single market."
TUV leader Jim Allister said: "There must be no weakening in resolve or straying into the bypath meadow of easements and extended grace periods.
"TUV has no interest in salvaging or patching up a protocol which is so fundamentally incompatible with British sovereignty and our constitutional position.
"Of course, there are huge adverse economic consequences with the protocol but for me the overriding issue is constitutional. Thus grace periods to help bed it in is nothing more than palliative care for the demise of the Union."
The European Commission has said it is exploring all "flexibilities" available within the protocol.