A DUP boycott of a north-south trade body in protest over Brexit's Northern Ireland Protocol has been dismissed as "pathetic".
Two DUP nominees to the board of InterTradeIreland have not been attending meetings in the months since taking up their posts in January, Belfast Live revealed.
DUP councillor Kim Ashton has now quit the board, saying her position was "conflicted due to the ongoing disruption" caused by Irish Sea trade checks.
Former DUP MP David Simpson is continuing as a board member, which attracts an annual wage of around £5,500 for northern reps regardless of attendance levels.
The DUP has not responded to questions over its representatives' absence, or whether it would seek to replace Ms Ashton on the board.
InterTradeIreland is among several north-south bodies under the remit of the North South Ministerial Council (NSMC).
SDLP Brexit spokesperson Matthew O'Toole said: "This is pathetic from the DUP, who have continually run away from the consequences of a hard Brexit they championed.
"InterTradeIreland is about maximising economic opportunity across the island of Ireland."
The South Belfast MLA said goods exports from north to south have increased, arguing that it comes as "businesses take advantage of the opportunities for seamless trade afforded under the protocol".
"The DUP will not be allowed to further jeopardise the prospects of prosperity for people on this island, having already helped create the problems of Brexit in the first place," he added.
Sinn Féin East Derry MLA Caoimhe Archibald said people want to see all of the political institutions of the Good Friday Agreement "fully functioning".
"That includes all north-south bodies. The DUP cannot cherry pick which institutions they want. There cannot be an a la carte approach to the Good Friday Agreement," she said.
"There also needs to be an acceptance of the reality that the majority want to see the protocol working.
"Farmers, traders, manufacturers and retailers have all made that clear repeatedly.
"It is time the DUP and the British government acknowledged that and implemented the protocol to provide the stability business needs."
Ms Ashton, a former DUP special adviser, said she resigned from the InterTradeIreland board last month and had asked not to receive remuneration during her absence.
It is unclear whether Mr Simpson also sought for his remuneration to be stopped.
Ms Ashton said: "As an elected representative of the DUP my position was conflicted due to the ongoing disruption caused by the NI Protocol.
"As I have not been in a position to attend the board it was wrong of me to continue to hold onto this position and therefore I took the decision to step down and allow the party leader to make a new nomination."
Mr Simpson, former MP for Upper Bann, has been approached for comment.
The DUP has previously been accused of boycotting the NSMC in opposition to the protocol after its Stormont ministers did not attend some meetings.
