Up to 65 jobs are at risk at Virgin Media Ireland.
The company said it is “entering a new phase of transformation” and may have to cut the jobs to improve growth.
The broadcaster and telecoms company currently employs 1,600 people in Ireland.
The move will affect jobs across all areas of the company and management will enter discussions with impacted staff members in the coming days.
A Virgin Media spokesperson said: “We are entering a new phase of transformation to ensure continued revenue growth.
“This involves making some difficult decisions which will impact a number of roles in the Virgin Media Ireland business.
“It is envisaged that up to 65 roles may potentially be impacted and we have entered a 30-day consultation period with people impacted.”
Green Party leader Eamon Ryan said it is extremely disappointing news.
“I don’t see how you can cut to get growth,” he said.
“It is another dark day in Irish media. We have had a lot recently where we have seen newspapers and radio stations in real difficulty.
“Cut-backs in the number of journalists and cut-backs in the number of programme-makers is not going to improve the quality of Irish broadcasting.
“So it is very worrying.”
Virgin Media Ireland is owned by international telecommunications giant Liberty Global.
It was known as UPC Ireland before rebranding in 2015. It bought television station TV3 last year.