A Stormont investigation is to take place into the suspension of checks at post-Brexit border posts in Northern Ireland.
The Department of Agriculture temporarily suspended physical checks at Larne and Belfast ports amid security concerns.
Its staff returned to work on Wednesday.
Members of the Agriculture Committee voted five to three in favour of an inquiry on Thursday.
Northern Ireland remained part of the EU’s single market for goods when the rest of the UK left at the end of the transition period.
This means that some products from Great Britain now have to enter NI through border control posts.
On 1 February, Mid and East Antrim Borough Council and then the Department of Agriculture, Environment and Rural Affairs withdrew staff amid claims of intimidation.
Threatening graffiti had appeared showing opposition to the NI Protocol in the government’s Brexit deal with the European Union..
The council staff later returned to work, but the department’s stayed out.
On Monday, the PSNI Chief Constable Simon Byrne said he had no evidence of a “credible threat” to them.
Later that day, Sinn Féin MLA John O’Dowd told the Stormont assembly that the information that led to the suspension of the checks was based on “misinformation” and the staff were used as pawns in a “very cruel game”.
Sinn Féin MLA Philip McGuigan told Stormont’s agriculture committee on Thursday that the confusion over what evidence the council had to suspend staff “warranted further investigation and scrutiny”.
He said some of the information was “simply not true” and that he believed the decision was “calculated and political by the DUP”.
DUP MLA William Irwin said staff safety was a priority and that there were “no consequences at all” from the decision to suspend staff, that it was a “sensible decision to make”.
Meanwhile, the DUP has withdrawn from party group leaders’ meetings of Mid and East Antrim Borough Council.
DUP Group Leader Gregg McKeen said: “The party group leaders meetings are not a decision-making body, but should be problem-solving forum.
“Unfortunately when details of discussions are leaked it negates the usefulness of this forum.”
“If these problems can be resolved we will be happy to resume participation,” he added.
Sinn Féin councillor James McKeown said the group leaders’ meetings should go ahead without the DUP.
“A special meeting of the council should be urgently convened and, if such a meeting is held, we will be calling for a full investigation into the events surrounding the withdrawal of workers from the port of Larne,” he said.
The Alliance Party’s Gerardine Mulvenna said that the DUP was “being reckless” with people’s futures.
“This shocking move has no thought for the ratepayers who are depending on us to provide help and support during an extremely tough time.
“Everyday decisions will now be held up indefinitely, which is simply not good enough,” she said.
Mid and East Antrim Borough Council has been asked for comment.