Fifty workers have downed tools and walked off the site of the new Queensferry Crossing in a pay dispute.
But as a gesture of goodwill, the consortium behind the multi-million-pound project has agreed to make an interim payment to the workforce while an investigation was launched.
With the Forth Road Bridge closed for urgent repairs on a cracked truss, the pressure is increasing to ensure the new bridge opens on schedule.
The workers are believed to all work in the marine yard in Rosyth.
This is where components of the bridge are assembled.
In a wildcat strike, the workers marched on the site offices to complain about what they believed was a huge discrepancy in the amount of wages they have received this month.
However, Transport Scotland stressed work on the £1.4 billion bridge, due to open in December 2016, had continued as normal during the rest of the afternoon.
The workers’ dispute is with the Forth Crossing Bridge Constructors, the consortium building the Scottish Government’s flagship project.
A Transport Scotland spokesman said: “We understand that approximately 50 of FCBC’s employees have reported an issue with the calculation of holiday pay under the new legislation.
“There are currently over 1,200 people employed on the project and other than the small number of affected employees, work has continued right across the site as normal this afternoon.
“Transport Scotland have a project team based on site who are monitoring the dialogue to help resolve the issue.”
It’s understood workers downed tools after they failed to receive their expected Christmas bonuses.
It was rumoured some had a £1,000 shortfall in what they anticipated getting in their December pay packets.
The dispute comes only days after Infrastructure Secretary Keith Brown praised the workforce for keeping the bridge on schedule for opening in 12 months time.
On Monday he thanked all those involved in building the new bridge for their hard work in getting to where it now was, and said he was very aware of the tough conditions experienced in the Forth, with 2015 being exceptional in terms of difficult weather, even during the summer.
Following hours of negotiations Michael Martin, the FCBC project director, said: “We have been concerned today at a holiday pay issue brought to our attention by some members of the workforce.
“We launched an immediate investigation to ensure that the payments which were made are in line with recent changes.
“We will be providing the workforce with a detailed breakdown of their holiday pay calculation.
“This is a complex tgask and will take some time to complete on an individual case by case basis.
“In the meantime, as a gesture of goodwill at this time of year, we have agreed to make an interim payment to the workforce and upon completion of individual breakdown analyses this payment will be reconciled in the New Year.”