The National Labor Relations Board (NLRB), the federal agency that oversees workers' rights, is to announce decision to prosecute Walmart for firing, discipling and threatening workers who went on strike or attempted to unionise, according to the group organising the strikes.

Our Walmart, a union-backed group, said the NLRB will prosecute the company for illegally firing and disciplining 117 workers, including some who went on strike in June. The board's decision will also include threats by managers and spokespeople aimed at discouraging them from striking, Our Walmart said.

Workers would potentially be awarded backpay, reinstatement of their positions and the reversal of disciplinary actions, Our Walmart said.

Our Walmart said it has filed more than 100 unfair labour practice charges against Walmart with the NLRB, including 20 illegal terminations and 80 disciplinary actions. The board said in September that it was looking into "several cases".

The alleged terminations and disciplinary actions relate to a demonstration in June by more than 100 workers who travelled to Bentonville, Arkansas, to take part in a rally at Walmart's shareholders meeting, according to OURWalmart. The threats relate to a statement by David Tovar, a Walmart spokesman, who said on CBS News that "there could be consequences" if employees did not report to work.

Workers have a legally protected right to protest.

Walmart said it would contest the decision by the NLRB. It said in a statement: “We disagree with this position by the Division of Advice. This is just a procedural step and we will pursue our options to defend the company because we believe our actions were legal and justified.

“The fact is, we provide good jobs and unparalleled opportunities for our associates. This is our busiest time of the year and we're focused on serving our customers and helping them have a great holiday season.”