Guinness Ireland is to cut its workforce in the Republic and Northern Ireland by 135 as part of an efficiency review of its operations.
The Diageo brewing subsidiary cited a "worsening business environment" as the reason for the cuts. It said it expected the alcohol drinks market in Ireland to be down 5 per cent this year.
The company said the cuts would be made from the sales, marketing and support divisions of the organisation.
100 people are to lose their jobs in the Republic, with a further 29 transferring to other parts of the organisation.
Diageo in Northern Ireland will reduce its workforce by 35, with a further 10 transferring to other Diageo operations there.
The company said it had briefed its employees and their representative body on the outcome of the review of its "business operational model" within Ireland; the review has been under way since March.
It said: "The newly structured organisation aims to ensure a better allocation of resources to areas of greatest potential for profitable growth and also involves a simpler structure which will lower costs and ensure quicker and more effective decision-making".
The cuts come amid growing speculation that Diageo is planning to close the famous St James's Gate brewery in Dublin on the grounds that it is uneconomical.
However, this has been strongly denied by the company.
On Wednesday, Diageo said sales of drinks such as Guinness and Baileys in Ireland had declined in the first six months of the year.
In a trading statement, the company said Irish sales have deteriorated in the second half across all categories. The company predicted a 5 per cent fall in Irish sales for the full year.
Diageo said the Iraq war and outbreak of the Severe Acute Respiratory Syndrome virus had hit demand for its products internationally.
