Permanent TSB has reported a profit of €53m for the first half of the year, before exceptional items and tax is taken into account.

The bank said it added 20,000 new accounts in the first six months of 2017, while its new mortgage lending rose by 62% year on year.

It also reduced its operating expenses by €8m compared to a year ago.

PTSB CEO Jeremy Masding said the profit figure was down on the same period of last year - but that was due to some one-off gains in 2016.

"This time last year there were a couple of one-off credits from the sale of some shares in Visa Europe and also from a provision write-back from house price inflation," he said. "I think a better comparator is the pre-impairment profit, which has gone up 18% from €59m to €77m, on the back of some really outstanding mortgage lending results."

However in its interim results Permanent TSB also reported a €6m impairment charge - which compares impairment write-backs seen in the past 12 months.

Mr Masding said that he was confident the lender would see further write-backs in its full year results - and that the current impairment charge was simply due to changes in the way it is reporting this figure.

One problem that does need further work to address, however, is the bank's stock of non-performing loans.

PTSB had almost €6bn worth of NPLs at the end of last year, and while that figure has been coming down slowly it today admitted that they remain "unsustainably high".

"We need from an NPL ratio of 28% to high single digit over the medium term," he said.

"That said we have 52% of our NPLs and I think the think the team has done a great job with nearly 40,000 customers in terms of helping them to get through the crisis.

"Unfortunately the untreated book still remains very high, and that is the book that we need to manage hard over the next few years."

"Managing hard" will likely see the bank deploy a number of measures - from speeding up the timeframe for arrears repayments to selling loans on to other companies.

However it may also see the bank secure the sale of a property - either through agreement or foreclosure.

PTSB said that non-cooperation is one of the reasons for its currently high level of NPLs - while others simply cannot afford the repayments involved.

Mr Masding said that each case would be treated individually, but ultimately the bank would be focused on resolving its bad debt issue.

"We need to, wherever we can, try and engage with customers and... our default position is to try and put them into a long-term treatment," he said.

"If we're going to help the next generation of Irish borrowers get onto the property, if we're going to contribute to the SME market growth, if we're going to be a real strong competitor in the Irish banking market, which we will be, we absolutely need to manage and resolve that 13% [of untreated NPLs] because it is a drag on our earnings."