More than 200 jobs have been announced for Dublin and Limerick.
150 of the jobs are on the way to Limerick, as H&MV Engineering is set to double its workforce to 300 over the next three to five years.
Taoiseach Leo Varadkar will be on hand for today's announcement.
CEO PJ Flanagan says a major recruitment drive is now underway.
He said: "We have a special taylor-made apprentice programme and graduate programme for employees.
"It is a great area to get into for young people in the area. We also have a number of different showcases going around schools to try and attract the young talent into H&MV."
In Dublin, up to 60 new jobs are to be created.
Flight catering business DNATA, which is part of the Emirates group, is setting up a base at Dublin Airport.
The roles will include chefs, finance staff and logistic personnel.
The company's Robin Pagett outlines why they chose Dublin.
He said: "This is and incredibly aviation-focused city and country with a great track record of passengers going through the airport.
"We suspect this year Dublin Airport will get north of 30 million passengers, that is people we should be supporting and providing great food and great meals for."