The number of billionaires in Ireland has almost doubled in recent years, according to the latest Sunday Times Rich List.

This year there were 31 new entrants in the Sunday Times Irish Rich List. A revival in manufacturing  has been credited with generating almost 50 percent of the new entrants to the annual list.

One Direction star Niall Horan entered the list of Irish millionaires 30 or under with an estimated fortune of €6 million ($7.8 million).

The fastest fortune was amounted by Limerick born brothers Patrick and John Collison, aged 24 and 22, who own the own online payment company, Stripe.

Colm Murphy, who compiled the list for the Sunday Times, said that their business rocketed to success straight away.

"It's due to the rocketing success of the company in Silicon Valley called Stripe," he said.

"Stripe is a company that makes online payments easier, the two brothers made their first fortune when they were still teenagers and that was £3 million ($4.5 million) they got for a company that they developed to sell management systems for eBay."

Digicel owner Denis O’Brien was the list’s biggest riser adding €1.4 billion to his fortune.