British Foreign Secretary Liz Truss is on the same page as the DUP in her approach to securing major changes to the Northern Ireland Protocol, the party's leader has said.

Jeffrey Donaldson said Ms Truss's pledges to reform the contentious post-Brexit trading mechanisms needed to be backed up with actions.

He indicated a "pause" on the DUP threat to collapse the power-sharing institutions at Stormont over the protocol would remain pending the outcome of renewed negotiations between the UK and EU over the Irish Sea trading barriers.

Ahead of a virtual meeting with Ms Truss this afternoon, Sinn Féin leader Mary Lou McDonald has said she and Deputy First Minister Michelle O'Neill will be pressing the need for constructive work, good faith and an end to "the kind of grandstanding... from the First Minister earlier today".

Speaking on RTÉ's News at One, Ms McDonald said it was signalled "right from the get-go" that Brexit was a "bad idea" and would have long-term negative consequences for the island of Ireland.

She said it was also clear that there would have to be special arrangements to protect the all-island economy, jobs, prosperity and the intergrity of the Good Friday Agreement.

"I think Liz Truss will have to accept and indeed honour the agreement entered into by her own government, which recognises the current political realities, recognises the fact that we live on an island, and that there has to be arrangements to ensure that the interests of all parties concerned are recognised and protected," Ms McDonald said.

"I would say to Liz Truss - if she was so anxious not to have trading blockages and so on, well then Brexit was not a very good plan to achieve that."

Ms McDonald said the arrangements on the island of Ireland are "finely balanced" and were achieved through many decades of hard work.

She said it would be "grossly irresponsible and indeed wreckless" for Ms Truss or anyone else in the British government to continue to push the boundaries for reasons "that are entirely self-serving".

She said it would be welcome if the DUP would "desist from this high-wire act" of threatening institutions in this way.

The reality on the ground, she said, is that the vast majority of people recognise the reason for a Protocol and why it is neccessary.

"And what people want are for the arrangements to actually work," she said.

"That's what businesses want, that's what people who get up every day and go out to work early in the morning want."

Ms Truss has taken charge of the UK negotiations on the protocol after David Frost's resignation from the British government last month. She will hold face-to-face talks with her EU counterpart - European Commission vice president Maros Sefcovic - later this week.

Ahead of those discussions, she had insisted she will not sign up to any arrangement that involved checks on goods moving within the UK.

Checks on goods moving from Great Britain to Northern Ireland are central to the operation of the protocol in its current form.

Ms Truss also reiterated the British government's threat to suspend elements of the protocol - by triggering its Article 16 mechanism - if a negotiated settlement with the EU proves elusive.

"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," Ms Truss said in the Sunday Telegraph. "I am prepared to work night and day to negotiate a solution.

"But let me be clear: I will not sign up to anything which sees the people of Northern Ireland unable to benefit from the same decisions on taxation and spending as the rest of the UK, or which still sees goods moving within our own country being subject to checks.

"My priority is to protect peace and stability in Northern Ireland. I want a negotiated solution, but if we have to use legitimate provisions including Article 16, I am willing to do that."

Differentiating between Ms Truss's comments and past statements from the government, Mr Donaldson said Ms Truss had been more "specific" about the actions London would take to ensure Northern Ireland's place within the UK market.

"Her focus on the movement of goods between Great Britain and Northern Ireland is particularly welcome because that is obviously a key area for us," he told BBC Radio Ulster.

"We have argued consistently that whilst we recognise that there needs to be checks on goods moving into the European Union, there is no need for checks on goods staying within the UK internal market and moving between Great Britain and Northern Ireland, that really has been at the heart of our opposition to the protocol."

Challenged on whether his repeated threats to pull ministers out of Stormont would ring hollow if he failed to follow through, Mr Donaldson said: "Of course, our possession with regard to continued participation in the Executive remains on the table, but what I want is a solution, that is where my focus is.

"That's why when others have been pushing for this or that, I've kept my nerve, I've kept my focus on what we need to achieve, which is an outcome on the protocol which removes the Irish sea border, takes away those checks on goods moving between Great Britain and Northern Ireland.

"And now we have a clear declaration by Liz Truss who is negotiating on behalf of the UK government that she shares this objective so that represents progress, but we want to see that progress translated into action and if we get that action, then yes, of course, that will represent real progress. That's what I want to see."

Mr Donaldson said Ms Truss had brought a "renewed focus" to the talks.

"I think that she recognises the need to make progress and quickly," he said.

The DUP leader added: "I believe that our strategy is working. I believe that we have focused minds of both the EU and the UK government in getting that solution. I welcome what Liz Truss has had to say. I think that she is now on the same page as us in terms of what a solution might look like.

"Of course, there are other matters that need to be addressed but I believe that the way in which we brought a focus on to this issue has ensured that progress is made. Not as much as I would like, not as quickly as I would like, but in the end getting the solution is what really matters."