A Stormont minister who ordered the withdrawal of port inspectors conducting Brexit checks had been informed that police did not believe there was an increased threat risk.

In asking senior officials to stand down staff at Belfast and Larne ports on Monday night, Edwin Poots expressed doubts that the PSNI had a “full understanding of the risks”, an Assembly committee heard.

On Tuesday, the Police Service of Northern Ireland stood by its position that the level of threat was linked to “low level” activity such as graffiti and online postings.

Officers insisted there was no evidence of loyalist paramilitary involvement, instead blaming the incidents on individuals or small groups disgruntled with the Irish Sea border between Great Britain and Northern Ireland.

The Agriculture committee heard on Thursday that Mr Poots decided action was needed after hearing concerns expressed by Mid and East Antrim council about activity at Larne port and feedback from “political colleagues” who had also reported threats.

Senior agriculture department officials, who outlined the chain of events leading up to the decision to committee members, revealed that a meeting with police to discuss the security situation had already been scheduled for the day after the decision to withdrawn was taken.

Mr Poots’s request on Monday evening for staff to be withdrawn was one of his last acts in office before temporarily standing down at midnight to undergo cancer surgery.

Permanent secretary at the department Dr Denis McMahon told the committee the chain of events started on January 21 when graffiti appeared in Larne threatening port staff.

The committee heard that at a meeting involving departmental officials and local council chief executives on January 28, an official from Mid and East Antrim council disputed the police’s assessment in regard to the level of risk.

Giving evidence to the committee, chief veterinary officer Dr Robert Huey, who attended that meeting, said: “I made the comment about the graffiti to members of the council that were there and that the police had been reassuring that it wasn’t a serious threat.

“And I was told by the representative there for Mid and East Antrim that was not the case and that the threat was serious and that I should be taking it seriously.”

Mr McMahon told the committee that Mr Poots called him on January 31 to voice concern.

“He stated that a local government officer had contacted him to alert him to potential health and safety risks as a result of threats to staff at the Larne port of entry,” he said.

“He also referred to conversations with political colleagues at a range of locations across Northern Ireland and other stakeholders who reported threats. He subsequently contacted the PSNI to provide more details.”

Mr McMahon said Mr Poots contacted him again at midday on Monday to discuss the issue.

“He stated that he was formally registering his concerns about the health, safety and security of Daera staff working at portal points of entry,” said Mr McMahon.

“Following this conversation I spoke to a senior PSNI officer (assistant chief constable Mark McEwan).

“He confirmed that the PSNI was gathering additional intelligence with the local police and that he was bringing together a stakeholders meeting for the next day, which I agreed to attend.

“He agreed to share a formal threat assessment following that meeting the next day, although at that stage his assessment had not changed significantly from the previous week.”

Mr McMahon said later on Monday Mr Poots met with council chief executives from Belfast and Mid and East Antrim.

“At the meeting concerns were highlighted relating to threatening graffiti, reports that vehicle registrations have been recorded and feedback from councillors and young staff feeling threatened and those primarily were around Larne but there was recognition that there was some issues in Belfast associated with rising tensions,” said the official.

Later that evening, Mid and East Antrim decided to pull its officials out of checking roles at Larne Port. Belfast did not take similar action.

Mr McMahon said Mr Poots called him again later that evening demanding that department officials were withdrawn from duty.

“He stated that he was very concerned about risks posed to staff and he was not convinced that the PSNI had a full understanding of the risks based on the continuous feedback he been receiving and he emphasised the duty of care of officials for their staff and noted that Mid and East Antrim council were already taking action,” he said.

“As Daera minister he was clear in demanding that action needed to be taken to protect staff.”

Mr McMahon said he subsequently held conversations with Dr Huey and agreed to proceed with a “precautionary” withdrawal of staff.

He told committee members he was still awaiting a formal written threat assessment from the PSNI. The permanent secretary said he would not pre-empt any decision on when staff would return to the checks.

He said new minister Gordon Lyons had signalled he wanted to be directly involved in that process.

Dr Huey told the committee that checks on live animals and some plants were still taking place and stressed it was only inspections on animal-based produce that was affected by the suspension.

He said the suspension was sustainable for a number of weeks but not any longer, warning that the EU could potentially take legal action if the situation continued indefinitely.

Sinn Fein committee member Philip McGuigan pressed the officials why the withdrawal decision had been taken if the police were not warning of increased risk.

Mr McGuigan said the decision-making process appeared to have been “heavily influenced and driven by the minister”.

Mr McMahon said the department had a legal duty to ensure health and safety of employees at work.

He said the legal framework set a “very, very low threshold for risk appetite”.

“I make no apologies for having a very, very low threshold for risk assessment,” he said.

He added: “No threat assessment can rule out all danger”

DUP committee member Harry Harvey praised Mr Poots’s position.

“It’s of paramount importance that you take all precautionary approaches and actions,” he said.

“I think Denis that early decisions are best when health and safety at work is concerned.”

He added: “I’m grateful the minister is putting you and your department’s safety first.”