The Wolseley building supplies group is to lay off 180 people nationwide and close four stores around the country.
Two of the shops to close are based in Tullamore, Co Offaly.
The company has blamed the downturn of the construction industry and new housing starts for the lay-offs.
Meanwhile, a medical electronics company is to lay off around 100 people at its plant at Fermoy in North Cork.
Sanmina-SCI, which manufactures a range of products including monitors for respirators and ventilators as well as MRI equipment, has its headquarters in California and employs around 400 people in Fermoy.
A company spokeswoman in California was unavailable for comment.
However, it is understood that the majority of workers being let go are on temporary contracts. The company is blaming the redundancies on the ending of manufacturing contracts which are not being renewed.
The plant was established in 1989 by SCI and became Sanmina-SCI in 2002 following a merger. A major expansion involving a €30m investment, supported by the IDA, was announced for the plant in June, 2007. However, it is understood that the current redundancies do not affect this.