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By Faith Hung

TAIPEI, Aug 22 (Reuters) - The head of Japan Exchange Group Inc (JPX) said on Friday that he favours longer trading hours for the exchange and a decision on the long-debated issue will be made this year.

JPX's current 5-hour trading day is the shortest among major exchanges in the world.

"Big brokers like Nomura and Daiwa are very reluctant to extend the trading hours because (it's) very expensive and they are not confident (about) the volume," said Chief Executive Officer Atsushi Saito.

"Net brokers use net trading systems. They don't have to pay so much costs, so they are the leader of introduction of night- time trading hours," he told reporters on the sidelines of a business event in Taipei.

"They are fighting very bitterly, so it's very difficult for me to make a decision. I'm waiting for it to cool down," said the chief executive. "Any decision must be made this year."

JPX could try to set up a night session, which was recommended by a JPX committee for discussion late last month. That could attract some full-time workers who come home and trade after dinner.

It also could extend the closing time from the current 3 pm, overlapping more with other Asian market hours. Or it could decide to keep current trading hours.

(Additional reporting by Emi Emoto in TOKYO; Editing by Kim Coghill)