Trade union Fórsa is seeking "immediate engagement" with management
Telecoms company eir has announced it is to cut 750 jobs.
In a statement, the firm said employees will leave as part of a voluntary incentivised exit scheme.
The firm also stressed that the job losses will not impact on the roll-out of broadband in rural areas.
The company said: "This has been launched in an effort to deliver costs savings and create a leaner, more agile organisation. In parallel, the company plans to simplify its products and business processes.
"Eligible staff have already or will shortly receive correspondence with a personalised financial estimate for their consideration.
"The terms of the scheme are aligned with previous similar schemes. A large percentage of the company’s field force is not eligible. The Minister and union representatives are being informed."
It added: "Today's announcement does not in any way impact on the company's ability to deliver on its recent contractual commitments in respect of our commercial rural rollout of Fibre to the Home (FTTH) to 300,000 homes and businesses."
The trade union Fórsa said it is seeking "immediate engagement" with senior management.
The union represents IT staff, some management grades and clerical officers at the company.
Fórsa assistant general secretary Eugene Quinn said the announcement followed widespread speculation about job losses following the recent change of ownership of the company.
He said: "We're obviously very concerned that more jobs are to be shed from the company.
"The indications from our members are that the company is seeking voluntary - not compulsory - redundancies.
"That would be in line with agreements we have in place to provide very strong protections for our members against forced job losses."
He added: "Nevertheless, I am seeking an early meeting to discuss the many implications of today's announcement for workers in the company."
Steve Fitzpatrick, general-secretary of the Communications Workers' Union (CMU) said: "We have been informed by Eir that the company intends introducing a voluntary exit scheme seeking to reduce worker numbers by 750.
"We have no indication that this will be anything other than voluntary.
"We will engage with the company on the detail and, in particular, to ensure that proper arrangements are put in place to cover work once the scheme takes effect."
The news comes days after a majority stake in the company was acquired by two French firms controlled by telecoms billionaire, Xavier Niel.
He acquired 65% of Eir through two companies: NJJ and Iliad.
It also comes after eir pulled out from the National Broadband Plan bid back in January.