Some 350 new jobs have been announced for Cork and Dublin.
Technology company eShopWorld is set to hire 250 new staff over the next three years - most of which will be based at its global headquarters in Swords.
The expansion will bring total employment at the company to almost 400 by 2019.
Elsewhere, Kings Laundry has announced 100 new jobs at its Cork facility, as well as 80 seasonal positions in Cork and Dublin for the coming summer.
The company is Ireland's leading supplier of linen and laundry services to the hospitality sector.
The new permanent positions bring the total workforce at Kings Laundry to over 550.
The company also announced it is investing a further €2m in its new state-of-the-art facility in Little Island in Cork, which opened in June 2016 following a €12m investment and creation of 40 jobs.
The Cork operation is the most environmentally friendly in Europe and has been specifically designed and built by Jensen with Kings Laundry.
Robert McGovern, Managing Director at Kings Laundry said: “When we first opened our new Cork operation, we gave a commitment to create 200 jobs within a two-year period.
“However, given the success of our business over the past year, we are now in a position to meet that promise twelve months early, which is an achievement we are very proud of”.