As house prices continue to spiral, Bank of Ireland insists its average mortgage is around £46,000. Mr Molloy said that despite this, the bank is concerned about the pace at which house prices are accelerating.

"Our average loan size is still relatively modest. The average loan size is up from £44,000 a year ago but there has been no dramatic increase."

Mr Molloy said it would appear that many first-time buyers have recourse to equity, say from their family, which is being used to fund new homes. Bank of Ireland's mortgage lending increased by 16 per cent in the six months to the end of September, in line with the overall growth in the Irish mortgage market.

Around 60 per cent of mortgages were to its existing customers and contained a good proportion of first-time buyers, he said.