The number of Bank of Ireland customers affected by the theft of laptops last year has risen to over 30,000.

RTÉ News has learned that following further investigations by the bank, more customers' details were on the four missing laptops than previously thought.

Last week, the bank said that medical records, bank account details, names, addresses and dates of birth of 10,000 customers were on the laptops.

The number of branches affected has increased from seven to 29.

The new branches identified are Bray, Ardee, Arva, Ashbourne, Athboy, Cavan, Bailieborough, Cootehill, Kingscourt Ballybay, Dunboyne, Carrickmacross and Ballyjamesduff,

Other branches are Oldcastle, Kells, Navan, Trim, Kill O' The Grange, Blackrock, Dún Laoghaire, Talbot Street and Greystones.

While the vast majority of customers whose details were on laptops were life assurance clients, a small numbers of mortgage holders were also included.

In an update, Bank of Ireland said an assessment had concluded that the risk of fraud arising from the thefts was 'very low', as the data on the laptops did not include bank account passwords, PINs or copies of signatures.

But the bank added that customers would be fully compensated if any fraud arose.

The bank said it is sending letters to affected customers telling them what type of personal data about them was on the laptops.

The details will not be included for security reasons, but they will be provided to customers on request.

A freephone number 1800 365 100 is open from 9am to 6pm from Monday to Friday.