DUBLIN (Reuters) - Ireland's permanent tsb (PTSB) (>> Permanent tsb Group Holdings PLC) said it was highly unlikely it would meet a target to resume dividend payments from 2019 due to the high ratio of non-performing loans (NPLs) it laid out fresh plans to tackle, sending its shares tumbling.

PTSB, which reported a 62 percent surge in mortgage lending in the first half of the year, has already delayed plans to return cash to shareholders by one year.

Other lenders, including state-owned Allied Irish Banks (>> Allied Irish Banks PLC), have resumed dividends as Ireland's banking sector recovers from a property crash a decade ago that required the most expensive state rescue in the euro zone.

"Is the guidance of declare '18, pay '19 ambitious? Yeah, it's very ambitious. Does it have a high probability? No but if we can make progress on the untreated (NPL) book, one never knows," Chief Executive Jeremy Masding told analysts on a call.

"Until we make progress on the untreated NPLs, I think it's going to be very difficult for us to have a conversation (with regulators)."

PTSB's shares accelerated their fall after Masding's comments and were down 16 percent at 2.10 euros by 0956 GMT.

Under pressure from regulators, PTSB said on Wednesday it would tackle the 47 percent of non-performing borrowers without a payment plan by offering a range of strategies, including accelerated workout, closures and portfolio sales, rather than forbearance - the temporary postponement of payments.

Those plans are intended to cut the bank's NPL ratio to a high single digit number over the medium term from what it said was an "unsustainably high" 28 percent of its loan book at the end of June.

The bank's rising mortgage lending, which grew at almost twice the industry average, increased its share of the rapidly recovering market to 10.8 percent and closer to the 13-17 percent level it targeted to capture by the end of 2018 when it re-listed on the stock exchange two years ago.

The 75 percent state-owned mortgage lender reported a pre-exceptional profit of 53 million euros (47.27 million pounds), down from 117 million euros a year ago. Last year it clawed back 61 million euros from money put aside for bad loans whereas it booked an impairment charge of 6 million euros this year.

"Momentum is strong going into the second half, I think the business has definitely turned a corner," Masding told Ireland's Newstalk radio station.

(Reporting by Padraic Halpin, editing by Louise Heavens)

By Padraic Halpin