Northern Ireland’s First Minister Michelle O’Neill has been blocked by the DUP from attending an economic summit involving Prime Minister Andy Burnham.

The Sinn Féin vice-president and Deputy First Minister Emma Little-Pengelly were both invited to attend the National Economic Council in Glasgow on Friday with other devolved leaders.

The DUP leader Gavin Robinson confirmed that his party colleague Little-Pengelly will not participate in joint engagements with O’Neill and permission will not be granted for the first minister to operate on a solo basis.

The move follows unionist anger over Sinn Féin’s involvement in protests which prevented a contentious Orange Order march in Portadown from passing along the mainly nationalist Garvaghy Road.

DUP leader Gavin Robinson said the first minister’s “arrogance will have consequences”, but O’Neill accused the party of being “reckless and irresponsible”.

“Her complaints today that she’s frustrated from engaging with the British Prime Minister within the sovereign United Kingdom will so be it because her law breaking must have consequences,” Robinson said.

A meeting of the party’s ruling officer committee was held earlier on Thursday.

Earlier O’Neill described the move to block the meeting with the prime minister as “reckless and irresponsible” and meant people in Northern Ireland “will not be represented”.

“This is a reactive stunt, driven by the DUP’s own internal pressures and electoral problems,” she said in a statement posted online.

Little-Pengelly said the concerns arising from O’Neill’s conduct and the “anger and hurt felt by many people across Northern Ireland, cannot simply be ignored or minimised”.

She said the decision comes after stopping a separate planned engagement with the President of Ireland, Catherine Connolly.

“I have requested a separate meeting with the Prime Minister to ensure Northern Ireland’s interests, including the urgent budgetary and funding challenges facing the Executive, continue to be represented directly,” she added.

O’Neill and other senior Sinn Féin figures have been interviewed by police investigating last month’s unnotified demonstrations in Portadown, with unionists accusing the party of acting unlawfully.

The Sinn Féin deputy leader has defended her involvement, saying it was the “right thing to do”.

The prime minister revived the National Economic Council over the summer to encourage greater collaboration between the nations and regions.

In a statement posted online on Thursday, O’Neill said: “The deputy first minister has decided to block representation from here at a major political event, which would include meeting with the first ministers of Scotland and Wales, and the British prime minister.

“The Economic Forum is taking place tomorrow in Glasgow, and this reckless and irresponsible approach of Emma Little-Pengelly means the people of the north will not be represented.”

Alliance leader Naomi Long said refusing to attend or preventing others from attending the meeting with the prime minister was reckless and put party interests ahead of Northern Ireland’s economic future and the needs of the public.

The Ulster Unionist Party leader Jon Burrows said the DUP’s decision “punishes Northern Ireland, not Michelle O’Neill”.

The DUP has been under pressure from unionist rivals and some within its own ranks over how to respond to the row over Drumcree.

Last week, DUP MP Carla Lockhart stepped down from the party’s officer board over their leader Gavin Robinson not withdrawing Little-Pengelly to force O’Neill from their joint Stormont office.

On Thursday Lockhart said she will follow her “own course” if the party does not seek to remove Sinn Féin’s Michelle O’Neill as Stormont’s first minister.

Robinson said that while O’Neill and her party colleagues “should be punished, that does not include punishing the rest of Northern Ireland”.

The Upper Bann MP, who last week quit the DUP’s ruling officer board in opposition to party leader Gavin Robinson’s approach, outlined her position in a letter to colleagues which she later posted on Facebook.

Other DUP representatives including assembly member Diane Forsythe have since backed Lockhart’s calls for O’Neill to be “removed from office”.

On Tuesday, Forsythe said that in the absence of such “meaningful action”, official engagements through the joint Executive Office should be stopped immediately as a “bare minimum”.

On Wednesday, a second DUP assembly member called for O’Neill to go.

Maurice Bradley said removing O’Neill “would not, in itself, require the Assembly to collapse”.

Bradley said the “attitude displayed by senior Sinn Féin representatives in the aftermath” of the dispute “have caused widespread anger and concern”.

He said the “arrogance and defiance demonstrated by repeated declarations that Michelle O’Neill is ‘going nowhere'” was “concerning”.

Last week, a court heard Police Service of Northern Ireland intelligence information that dissidents may have mounted gun attacks on police had officers cleared a path for the parade.

Bradley’s statement added: “No one is above the law, regardless of their political position. There cannot be one standard for ordinary citizens and another for those holding the highest offices in Northern Ireland.”

Bradley added that the party “must stand together” and “support Carla Lockhart”.

Other party members including former MP Lord McCrea and Mid Ulster councillor Clement Cuthbertson have also backed Lockhart.

Party leader Robinson said last week that he was “sorry” to see Lockhart quit the DUP’s officer board but added that she remained “a key part of our team”.

Speaking on the BBC’s The View programme, the Robinson said the party had reached a democratic decision on how to deal with the Drumcree fallout.

He questioned whether it was necessary to “punish everyone in Northern Ireland when actually we should be punishing those who broke the law”.

“We have considered all options and we keep all options on the table,” he added.