Joao Vale de Almeida, the bloc’s ambassador to the UK, said it is unhelpful to “keep agitating the issue” of triggering Article 16, ahead of discussions this week.
Ms Truss said she will suggest “constructive proposals” to her EU counterpart, Maros Sefcovic, during their first face-to-face talks, at her Chevening retreat on Thursday.
But she said she is “willing” to invoke Article 16, which would suspend parts of the treaty designed to prevent a hard border with the Republic, if a deal cannot be struck.
Mr Vale de Almeida told Sky News’s ‘Trevor Phillips on Sunday’: “We’ve heard this before from the government, so we’re not surprised. We are not too impressed.
“We still believe it’s not very helpful that we keep agitating the issue of Article 16. I think what we should focus on – at least that’s where we are focused on – is trying to find solutions for difficulties in the implementation of the protocol.”
He called for “new momentum” in the talks, adding: “We are eager to reconnect but we are even more eager to find compromises because we need to move on. It’s been too long.”
Writing in the Sunday Telegraph, Ms Truss said it is her “absolute priority” to resolve the “unintended consequences” created by the protocol to maintain peace in Northern Ireland.
“When I see Maros Sefcovic this week for our first face-to-face talks, I’ll be putting forward our constructive proposals to resolve the situation.”
The current issues are “myriad and manifest”, she argued, citing issues such as bureaucracy on sending parcels between Northern Ireland and Britain and problems in procuring kosher food.
“I am prepared to work night and day to negotiate a solution,” Ms Truss said.