Qatar National Bank  is weighing a potential bid for Denizbank , the fast-growing Turkish arm of euro-zone debt casualty Dexia in a deal potentially worth up to $6 billion, people familiar with the matter said.

QNB, 50 percent owned by sovereign wealth fund Qatar Investment Authority (QIA), would be the latest Qatari interest in Dexia's assets after Qatar's royal family bought its Luxembourg-based private bank last week.

An investment group that belongs to members of the Al-Thani royal family acquired Dexia's Banque Internationale Luxembourg. The family also runs investment groups including QIA, which has invested in European banks including Barclays in the past.

Bank of America Merrill Lynch is evaluating strategic options for Denizbank, a statement said this week. 

Bankers said that QNB was motivated to buy Denizbank, but said that an acquisition would be a stretch for the firm, even though it is the largest lender in the country.

"A purchase would give them scale and the Gulf Arab region is in love with Turkey. Still, Denizbank, would be a large trade for them," one banker said.

QNB, the largest lender in Qatar, has a market capitalisation of around $25 billion according to Reuters data.

The firm has been expanding abroad, with operations in Syria, Jordan, the UAE and Switzerland, and its third-quarter net profit rose 27 percent as it increased lending in Qatar's booming economy.       

The bank could also use its in-house investment banking team and not rely on outside advisors for the bid, one banking source said.     

In August, QNB set up a $7.5 billion euro medium term note (EMTN) programme to fund its banking operations. The lender picked Barclays, HSBC and QNB Capital as arrangers for the bond programme. - Reuters