The Communications Workers Union has been that told its threat of industrial action at An Post is irresponsible and unacceptable.
Employers group IBEC said An Post must be allowed to deliver its change agenda to ensure improvements.
IBEC said the taxpayer, the public and the business community are entitled to expect improved levels of customer service, efficiency and value for money from the company, under the change agenda proposals.
The CWU has served An Post with 14 days notice of strike action saying that their workers need wages increased to cope with the cost of living.
Last night the Government warned the strike could allow a new postage company to enter the Irish market.
IBEC's director of industrial relations Brendan McGinty said the CWU's planned industrial action could damage An Post's future.