Three separate firms have announced they will create 500 jobs based in Dublin and Shannon, Co Clare.

Ryanair has announced it will create 200 IT jobs to develop an improved digital platform including a new mobile app.

The announcement was made as Taoiseach Enda Kenny and Minister for Finance Michael Noonan opened the airline's new Dublin offices.

The jobs will be primarily in technology, software development and digital marketing.

A pharmaceutical company has said it will create 200 jobs in Blanchardstown, Co Dublin over the next two years.

Alexion has announced that it is expanding its operations in Ireland with an investment of €75m in a new global supply chain facility.

The company is building a packaging, office and warehouse facility at College Park in Blanchardstown.

It is expected that an additional 200 construction jobs will be created as a result of the expansion.

The company currently employs 60 people at its facility in Park West.

In February, it purchased another site in Athlone.

Finally, Pepper Asset Servicing plans to create 100 positions over the next 12 months, with recruitment already under way for 50 jobs in Shannon, Co Clare.

The jobs follow the securing of contracts including the National Asset Management Agency (NAMA), Danske Bank and CarVal Investors.

The other 50 jobs are expected to be split between Dublin and Shannon.

Ireland 'wide open for business'

The Taoiseach has told a conference hosted by the US Embassy that Ireland is "wide open for business".

Speaking at the Smart Economy event in Dublin, Mr Kenny said the best solutions he sees emerging from the country are based on collaboration.

He said that is where industry, educators, researchers and government work creatively and collectively to identify new solutions.

There is a clear plan for the development of the economy for the future, a plan based on enterprise and not on speculation, he said.

Mr Kenny added that by 2020 the Government wants to have replaced all the jobs lost during the catastrophic economic situation.

During his visit to the United States for the St Patrick's Day celebrations he told business executives to contact him anytime, he said.

He added: "I said to people, you're all involved in the business, here's my phone number if you want to call me.

"Christ, I've been getting calls from Adelaide and New Zealand and everywhere.

"Some of them are not what you might expect. Not all about industry."