UNITE the Union is set to legally challenge the policing of striking workers after the PSNI mounted an evidence gathering operation during a picket of the Hovis site near Boucher Road.
Members of Unite and the Bakers, Food and Allied Workers Union have maintained 24-hour picket at the bakery giants' Apollo Road site since Friday.
The workers are seeking a 10 per cent pay rise that would bring their wages in line with their colleagues in Britain.
Supermarkets across the North have been impacted by the strike action as a shortage in Hovis products.
On Monday, the PSNI dispatched several vehicles, including a CCTV Land Rover, to the Hovis site, keeping the striking workers under surveillance.
Unite's Regional Co-ordinating Officer, Susan Fitzgerald, condemned the PSNI's action as "disgraceful and heavy-handed".
"The actions today have just strengthened the resolve of all union members here," she said.
"If they try anything else like that, what we will do is appeal to the whole city of Belfast and further afield, because at it's heart this is about fair pay for Northern Ireland workers. Workers here are not being paid equally with their colleagues across the water."
She added: "They are making a mistake if they think that they can try and frustrate this – this is a very effective picket; shelves in supermarkets are empty and that is the proof in the pudding."
A source at Unite told belfastmedia.com that the union plans to challenge the PSNI's application of Covid regulations to striking workers.
"We don't want the threat hanging over the heads of workers when they need to defend themselves and their terms and conditions," he said.
People Before Profit Councillor Matt Collins branded the PSNI's actions as "outrageous".
"These workers kept us fed throughout the pandemic, the very least they deserve is decent wages for their efforts, especially since their employer makes millions in profit," he said.
"Workers have a right to take strike action and to picket their workplace and they are doing so in a safe way."
A workers’ strike at Hovis’ Belfast facility on Apollo Road has entered day six, with talks between management and unions breaking down: https://t.co/DUQLRzCjd1
— British Baker (@BritishBaker) May 20, 2021
Meanwhile, the PSNI is remaining tight-lipped about the nature of its operation at the picket.
Asked why the police were monitoring the strikers, a police spokesperson said: "Police officers are currently maintaining a presence at a strike at industrial premises on Apollo Road in South Belfast."
A Hovis spokesman said: “Unions representing staff at the Hovis (Ireland) Belfast site have balloted their members for strike action. Hovis has made an above inflation pay offer of 2.5 per cent each year for three years which we believe is fair and reasonable given current market conditions. The claim made by both unions is for a 10.5 per cent pay increase, with additional elements taking it to approximately 15 per cent, which is clearly unsustainable.
“Hovis is disappointed to hear the results of ballots for strike action, given how unsustainable the claim is. We continue to seek a resolution that is acceptable to all sides and are committed to reaching a conclusion to this action as soon as possible.
“We operate in a tough and competitive market subject to increasingly higher operating costs but still offer pay and conditions that are market comparable as we continue to sustainably grow the business.”