SIPTU has told an Oireachtas committee that some staff at Newbridge headquartered Bord na Mona are being treated "abysmally".
Bord na Mona is making up to 430 of its workers redundant.
The firm is closing 17 of its 62 active bogs, in a decarbonisation programme.
150 of these job losses are expected to take place before April.
The Finance Minister signed-off on the terms of the redundancy package last month.
Staff will get four weeks pay per year of service, up from 3.
The cap has been incresed from 78 weeks pay to 104 weeks pay.
There is no age limit.
SIPTU's Willie Noone appeared before the Oireachtas Committee on Climate Action.
He says there have been changes to pension arrangements for workers leaving the company before retirement age