NAYPYITAW, Myanmar (Reuters) - The leading local partner in the Dawei port and industrial complex in Myanmar being led by Thailand's Italian-Thai Development Pcl said on Wednesday he was pulling out of the project, adding to doubts about its viability.

Reports have circulated that Max Myanmar Group, which owns 25 percent of Dawei Development Co Ltd, had become lukewarm about the venture.

"We are pulling out from the project gradually," Zaw Zaw, Max Myanmar's owner, told Reuters by telephone when asked about the reports. He declined to elaborate further.

Italian-Thai was already thought to be struggling to find financial backing for the $50 billion, 250 sq km (97 sq mile) complex that was planned to include a deep-sea port, steel mills, refineries a petrochemical complex and power plants, although the government had already vetoed a coal-fired power station.

The project was agreed with the military government that ruled Myanmar until March 2011.

The energy minister in the quasi-civilian Myanmar government that succeeded the junta told Reuters in February that at least two other special economic zones would be developed more quickly than Dawei.

The government of Thailand has been more enthusiastic. In May it approved a budget of 33.1 billion baht ($1.1 billion) for infrastructure in the west of the country that would provide links with the border area by Dawei.

Thailand justified the work, to include a four-lane road, government offices and homes for Thais who might work in Myanmar, by saying many Thai firms wanted to set up in Dawei and the government had to support that investment.

(Reporting by Aung Hla Tun; Writing by Alan Raybould; Editing by Martin Petty and Ed Lane)