Labour MP Kate Hoey has been accused of putting Brexit before peace in Northern Ireland in a sustained verbal attack at a House of Commons committee.

Colum Eastwood, the leader of the nationalist SDLP party, said recent remarks by Hoey and other Brexit supporters about the Good Friday agreement not being sustainable were “very, very destabilising” for local communities.

“I, for one, will not have the Good Friday agreement torn up just to facilitate a very awkward negotiation that’s going on between the United Kingdom and the European commission,” Eastwood told her.

Hoey, who is from Northern Ireland, sits on the Northern Ireland affairs committee, which was taking evidence from witnesses from the region on devolution and democracy on Wednesday.

The committee was sitting the day after Ireland’s deputy prime minister criticised Hoey for making “reckless” and irresponsible remarks after she declared that the Good Friday agreement that brought peace to Northern Ireland 20 years ago was unsustainable.

A tense exchange ensued after she asked Eastwood if it would be possible to tinker with the Good Friday agreement in a bid to restore the regional assembly, which collapsed 13 months ago.

“Getting rid of mandatory coalition, as you call it, is not tinkering,” said Eastwood in a reference to power-sharing between Sinn Féin and the DUP in Stormont. “That’s a fundamental change in what the Good Friday agreement represents, and what the Good Friday agreement, at its very core, represents is peace,” he said.

“I noted your comments, and I noted other people’s comments who seem to be more focused on ensuring we get out of the customs union and single market and we have a Brexit no matter what.”

Hoey, who supports the UK’s exit from the EU, hit back, saying her comments were “nothing to do with Brexit”.

Eastwood replied saying he thought her comments, along with similar remarks by Brexiter Daniel Hannan and the Conservative MP Owen Paterson “seemed fairly co-ordinated to me”.

Hoey said she had never suggested “tearing up” the Good Friday agreement and was supported by the committee chairman, who warned that such accusations did not do anyone any good.

Earlier, the loyalist blogger Jamie Bryson, a representative of Unionist Voice Policy Studies, accused Hoey’s critics of exaggerating the threat to peace in Northern Ireland.

He agreed with Hoey it was possible to support peace and be against violence and still be critical of the political process. He said equating debate about the Good Friday agreement with a support for violence was “a moral blackmail at the heart of the GFA”.

“Who’s going to engage in violence?” he asked rhetorically. “It’s an easy way to shut down debate.”

