Union negotiations with Tata Steel broke down on Friday, with the company accused of a “callous attack” on its staff.
The GMB union said: “State sponsored decimation of a community, its jobs and its industry will never get the support of the GMB.”
It said Tata and the UK government “should be ashamed of their abandonment of this proud industry and the chaos their plan is going to wreak on the community”.
It added that the offer is given in the context of “the largest number of redundancies to happen in the business since they took over in 2007”, and the first time members have faced compulsory redundancies.
About 2,800 workers will lose their jobs, mostly in Port Talbot, as Tata Steel restructures its UK operations.
Employees would receive a minimum of £12,500 and none would be made redundant before September 2024, said Mr Nair.
Tata Steel will close both blast furnaces in Port Talbot this year, and will then begin building a £1.25bn electric arc furnace on the site.
The blast furnaces will close by September, with construction due to begin on the electric furnace in the summer of 2025.
The company has addressed staff directly following the failure to reach an agreement during talks with unions in London last week.
Members of the Unite union have already voted to strike over Tata Steel’s restructuring plans, which will lead to 2,800 job losses.
Two other unions, Community and GMB, are due to end their own ballots on Thursday.
