A key suspect in last month's bombing at a Bangkok shrine that killed 20 people has fled to Turkey, Thai police said.

The claim is another indication that the attack could be the work of members of China's ethnic Uighur minority who have sympathisers in Turkey.

But a senior Turkish government official denied that the man had escaped to the country.

"There is no record of the suspect having entered Turkey," the official said in an email.

"Nor have the Thai authorities informed us that a terrorism suspect was traveling to Turkey."

Thai police had previously said the man, carrying a Chinese passport in the name Abudureheman Abudusataer, may have directed the August 17 bombing of the Erawan Shrine.

Investigations revealed that he left Thailand on August 16 for Bangladesh, and police speculated that he might have gone to China.

However, national police spokesman Prawut Thavornsiri said that information gathered by Thai police and Bangladeshi officials showed that the man departed Bangladesh's capital, Dhaka, on August 30 and travelled to Istanbul in Turkey as his final destination, via New Delhi and Abu Dhabi.

"He departed Dhaka on August 30 for Delhi by Jet Airways," Mr Prawut said.

"From Delhi, he continued his travel to Abu Dhabi, and from Abu Dhabi he traveled on August 31 to Istanbul. This is his final destination. It's clear."

This bolstered the theory that those behind the blast are Uighurs from the Chinese region of Xinjiang who have close ties to Turkey.

Several of the 12 bombing suspects for whom arrest warrants have been issued are believed to be Turkish.