Qatar National Bank  has made a revised, higher bid for Denizbank, the Turkish unit of stricken Belgian lender Dexia, four sources familiar with the matter said.

"The bid has been reactivated, and is on the table," said one source.

"The new offer is closer to what Dexia is expecting," he added, saying that QNB's original offer had been dismissed as too low. No immediate comment was available from QNB and their advisors Citigroup declined to comment. The sources spoke on condition of anonymity as the matter is not public.

Denizbank is worth $5.9 billion in the current market after a 49-percent run up since news of the sale emerged, and Dexia is understood to be looking for up to $4 billion for the bank.

A second source said that QNB had originally bid 1.1-1.2 times Deniz's book value and the Belgian government had wanted 1.5 times book. It was not clear what the revised QNB bid was.

Dexia, crippled by the euro zone crisis, has been trying to sell the Turkish bank for over six months. Two other bidders, HSBC and Sberbank pulled out, leaving QNB as the sole suitor.

People familiar with the matter told Reuters last month that Dexia had considered the Qatari offer too low, and was not willing to sell the healthy Turkish business - which gives access to a fast-growing market - in a fire-sale.

Dexia mandated U.S. investment bank Bank of America/Merrill Lynch in October to advise on the sale. UBS is advising the Belgian government. Shares in Denizbank rose after the news and were trading 5.3 percent higher at 15.85 liras. - Reuters