The Data Protection Commissioner is investigating a data security breach made by Irish mortgage campaigners New Beginning.

According to The Mail on Sunday, 1,500 homeowners had their financial details sold to a €2bn overseas investment fund that aims to buy up 1,500 distressed homes here.

The Malta based fund Arizun reportedly used the New Beginning database to calculate the profitability of the scheme before approaching Irish banks to negotiate the purchase of thousands of distressed loans.

But Ross Maguire from New Beginning denies selling clients' details and says the information was sent by mistake.

New Beginning have now released a statement on the data-protection breach which states: "In developing the programme we analyzed a sample of cases from New Beginning’s database to see if a move from a mortgage repayment to rent would benefit clients. No personal details were required and it was agreed at the outset only general information could be shared with Arizun/Casa Mundi with all names, details and identifying information withheld.

It was also agreed that Casa Mundi would pay towards the cost of New Beginning employees to ensure that this engagement did not detract from our other activities.

The data was sent to Arizun Casa Mundi in two tranches. In one of these two tranches a New Beginning contractor mistakenly included identifying information, including names and address. The consultant, who was on a short-term contract, is no longer with New Beginning. Once the error was noticed we contacted Arizun/Casa Mundi which agreed to delete the information sent in error."

Ross Maguire, co-founder of New Beginning, said: “We are sorry for this lapse on our part. As well as ensuring that the data was destroyed we hired a consultancy firm to review our data-protection measures in general. In the next few days we will write to each of the people on our database whose details were passed on in error to apologise for this lapse on our part and to assure them that there details were not used in any way.”