Meanwhile, it is also organising a series of nationwide demonstrations at the sites of supermarkets stocking packaging produced by the Austrian-owned company, which includes major names such as Kellogg's and Unilever.
According to Unite, MMP planned to close its Bootle plant without consultation, breaching both UK and European legal obligations.
The move came after employees were had been locked out of the plant since 17 February over redundancy terms and selection criteria, which led to strike action in early February.
Earlier this month (20 March) MMP informed 49 members of staff that they had been made redundant, before announcing the closure of the plant on 29 March.
Unite claimed that the conduct of the company was "among the most shameful [we have] encountered".
The union is arranging to issue an application in the Employment Tribunal claiming a protective award on behalf of all union members made redundant, and the union will seek the maximum remedy of 13 weeks gross pay for each member.
In addition, it is likely that other claims will be pursued on behalf of the union and all individual members if the decision to dismiss the union’s members is not reversed. This will include claims of unfair dismissal and potentially claims arising under the TUPE Regulations.
When it announced the redundancies, MMP said that staff were offered redundancy packages over the statutory amount.
Regional officer Phil Morgan said: "Unite is appalled by the outrageous behaviour by MMP management. It is among the most shameful treatment of workers I have ever come across. MMP clearly thinks it is above the law.
"This is a new low in long-distance dismissal. Over a hundred loyal workers – some of whom have worked there for 30 years, since leaving school – were handed letters sacking them with only a moment’s notice.
"Such behaviour cannot be acceptable from employers, but when a profitable company such as MMP behaves so disgracefully, we will challenge it.
"MMP owes our members money. In these desperately tough times, every penny is needed yet because of MMP's greed, workers with young families now cannot pay their bills and mortgages.
"We now look to the courts to remind MMP that it cannot ignore its redundancy obligations and its duties to UK workers."
MMP declined to comment.
