Some 485 jobs have been created by three US firms as Taoiseach Enda Kenny used a trip to New York to urge American business chiefs to think, buy and invest in Ireland.

IT giant HP plans 150 R&D posts and 130 technical and support roles at its bases in Galway and Kildare, while pharmaceutical giant Abbott will recruit 175 at its Sligo manufacturing plant and gaming firm Big Fish will take on 30 new staff in Cork.

The jobs boost was announced as the Taoiseach used a special forum at New York University to lobby 100 executives and investors to put Ireland top of their business list.

"You know how determined we as a nation can be once we put our mind to something," the Taoiseach said. "You too can play your part. Whether it is by increasing investment, or creating new jobs, or buying from Irish suppliers, or encouraging your colleagues, your friends, your business contacts to think Ireland and think Irish, every little counts."

The Invest in Ireland Forum at New York University had been arranged by former US president Bill Clinton after attending the Global Irish Economic Forum in Dublin last October. All the investments have been backed by IDA Ireland.

The biggest project has been signed off by technology giant HP which is looking for highly qualified engineering and computer science graduates, in addition to experienced engineers, for R&D. Staff will be taken on in the west of the country and in HP's Leixlip base.

Abbott said its 85 million euro expansion was designed to support future pharmaceutical developments in key therapeutic areas of virology, oncology and nephrology.

The new permanent posts will be in engineering, quality and pharmaceutical science while the investment will create 150 temporary construction jobs before the site opens in 2014.

Online gaming firm Big Fish said it was expanding its Cork-based cloud gaming research and development initiative.

Tanaiste Eamon Gilmore and Jobs, Enterprise and Innovation Minister Richard Bruton have also travelled to New York for a series of enterprise engagements to encourage investment by US firms with no base in Ireland.