A leading UK expert on ticket touting has offered to provide evidence to the Government and authorities here on how markets are being "rigged" by organised gangs.

Reg Walker of Iridium Consultancy previously gave evidence to the House of Commons on criminal gangs involved in touting, including a Dublin-based gang.

Speaking on RTÉ’s This Week after last night's sold-out concert by U2 in Croke Park, and reports of tickets selling for huge multiples of their face value, Mr Walker said those involved in organised touting were making vast sums of money.

"This is industrial harvesting of tickets to create a rigged market to artificially hike up prices that fans have to pay," he said.

Mr Walker,who is on the UK Government's panel of experts on ticket touting, said he would willingly provide evidence to authorities here as a result of investigations in Britain and Europe.

The Government is currently examining possible changes to the law to tackle touting and the Competition and Consumer Protection Commission has also launched an examination of the tickets market.

Mr Walker said organised touts use sophisticated, aggressive software that often incorporated stolen source codes from the sites of primary ticket sellers.

He explained the gangs used hundreds of identities and credit cards to attack the main sites, harvest thousands of tickets which are then put up for sale on some secondary ticket re-sale sites.

According to him there is evidence in some jurisdictions of collusion between some touts and secondary sellers.

Fans in Ireland and abroad have increasingly complained about how when ticket sales open for major events they sold out in minutes and minutes later hundreds, often thousands, of tickets are up for sale on secondary sites at vastly inflated prices.

Mr Walker said it was "nonsense" to think that consumers and fans parted with hard earned money to buy tickets and then a few minutes later decide they could not attend the event, resulting in huge numbers of tickets going up for re-sale.

He said some "super touts" were making up to £10m (more than €11m) a year from this market.

Asked about the involvement of a Dublin criminal gang he said "we have substantial evidence of a very serious organised crime gang operating in the Dublin area with business interests and a significant presence in Spain. They are backing or financing touts in the UK."

He said they were operating on the basis that this activity provided a good revenue stream and was virtually risk free.

According to Mr Walker a dangerous Israeli-based gang is also involved in major touting and new gangs are emerging.

He said part of the problem is that governments are using civil law and gangs are willing to defy this. He urged that efforts to tackle massive touting also needs the creation of criminal offences.

Police forces, he said, needed proper powers and also needed to understand that the vast sums made are going back to dangerous people involved in other forms of crime, apart from touting.

He has advised event organisers in the UK on ways to tackle touts such as names on tickets, reducing or eliminating e-tickets and the use of photo IDs.

However he added that while photo IDs do help they are not foolproof.

In the UK they have encountered gangs using paid "walkers", where one person with a batch of tickets and a photo ID will "walk-in" say four or five fans on tickets sold by the touts as vast prices.

He also outlined how he recently worked on one major tour examining over 1 million ticket sales manually to identify tickets that were likely to have been obtained using aggressive software and then moving to cancel those tickets and putting them back on the open market.

Mr Walker said he was previously opposed to laws capping the price of re-sale tickets but because of the scale of organised touting he now thinks a 10% cap on re-sale tickets is one legal option.

He said this has worked in some countries.

Other measures governments should consider, as the UK has, is a ban on the use of aggressive software for ticket purchases.