Northern Ireland's technology companies must think big if they are to realise their potential, according to a successful US technology entrepreneur.

David Kirk laid down the challenge after a meeting in Belfast of the Irish Technology Leadership Group, made up of Silicon Valley investors with an interest in boosting technology businesses in Ireland.

Mr Kirk, who was born in Belfast but now lives in San Francisco and fomerly held senior roles with AOL and Cisco Systems, said the group had seen around 70 business plans from Irish technology companies.

Twelve businesses from across the island of Ireland pitched to the venture capitalists. 1A number of Northern Ireland businesses had the potential to become £100m companies, said Mr Kirk.

"We saw at least three or four world class technology opportunities. But they need the right funding and the right mentoring to play on the world stage," he added.

However, a lack of ambition and vision hampered technology businesses in Northern Ireland, Mr Kirk said.

"We were impressed by what we saw, but depressed by the lack of ambition and scale in attitude," he said.

"We saw more potential and opportunities than the companies themselves. With the right encouragement and with government help, they could be significantly bigger than they were projecting. But there needs to be much bigger thinking.

"If they threw down the gauntlet and said, 'let's race to the £100m,' a company from Northern Ireland could make it there," the entrepreneur added. The ITLG is a group of Irish and Irish American senior executives based in Silicon Valley. The visiting delegation, dubbed Silicon Valley Comes to Ireland, was made up of venture capitalists and business chiefs, including representatives from technology giants Cisco and Intel. The group aims to help the island of Ireland address the challenges of embracing new technology opportunities and to ensure that Ireland remains a strategic area of investment and opportunity for US technology companies.

They attended a reception hosted by First Minister Peter Robinson and Deputy First Minister Martin McGuinness as part of their visit last week, in addition to meeting with Enterprise Minister Arlene Foster, Employment Minister Sir Reg Empey and Invest NI chief executive Alastair Hamilton.

Last year the group met in Dublin.