Implementing the protocol in full would result in "an economic tsunami" hitting Northern Ireland, DUP leader Sir Jeffrey Donaldson has said.
Responding to a tweet from a member of the US House of Representatives, the DUP leader said that calling on the Northern Ireland Protocol to be implemented in full was "such folly".
He said: "Implementing the protocol in full means ending grace periods, with an economic tsunami hitting Northern Ireland. Power sharing only works with cross community consensus.
"There is no unionist support for the protocol. The protocol will destroy the GFA if not dealt with."
US House of Representatives' member Brendan Boyle had called on the UK Government to "implement fully the NI Protocol, which avoids a hard border on the island of Ireland, preserves the integrity of the EU Internal Market, and protects the Good Friday Agreement in all its parts".
Earlier on Sunday, Alliance Party leader Naomi Long told Sky News that she understood border friction issues were "difficult" for unionists, but that it was an "inevitability as a consequence of Brexit".
"Unfortunately, Brexit put borders and border friction back on the agenda, and that is very difficult for the very delicate ecology of Northern Ireland to deal with," she said.
The DUP has refused to elect a speaker to the Northern Ireland Assembly in order to put pressure on the UK Government to change or remove the protocol.
A US delegation is currently visiting Ireland, the UK and Belgium as part of a trade mission and to "underscore the significance of the Good Friday Agreement".
DUP East Antrim MLA Gordon Lyons said the DUP looks forward to engaging with the US delegation later this week, but added that "they must recognise that the protocol has undermined the Good Friday Agreement".
"Since the protocol's inception, not one unionist MLA or MP has supported it, yet it has continued to have the support of Washington throughout," Mr Lyons said.
"Key influencers in the US administration have continually demonstrated a total misunderstanding of the Belfast Agreement, the border and consent.
"They should admit their one-side mistakes if they want to be taken seriously by unionists.
"It is high time the American administration recognised the fundamental importance of securing the support of both unionists and nationalists. Without such support devolution cannot function."
There has been controversy over the Northern Ireland Protocol since its inception.
Created to avoid the return of checkpoints along the Irish border, after years of negotiation it was agreed that new Brexit regulatory and customs processes would be placed along the Irish Sea.
Both London and Brussels agreed to this as part of the final Brexit negotiations.
Since its implementation in early 2021, the EU and UK agree that the protocol does not work as smoothly as it should, and both sides engaged in further negotiations.
Grace periods were introduced for some new Brexit trade rules in the protocol, meaning retailers and exporters do not yet have to adhere to all the checks and standards required.