Thailand will sign a $1.7 billion deal to develop the first phase of the long-delayed Dawei Industrial Zone in southeastern Myanmar in the first week of August, Thailand's secretary-general of the state planning agency said.

The project is arguably Southeast Asia's most ambitious industrial zone - a 250-sq-km (100-sq-mile) deep-sea port, petrochemical and heavy industry hub along the slim Thai-Myanmar peninsula.

The signing will take place in Naypyidaw between Japan, Thailand and Myanmar, Arkhom Termpittayapaisith, secretary-general of the National Economic and Social Development Board, told reporters.

"The Dawei project will link production in the southern economic corridor and will help Thailand enter into the supply chain of globally important industries. This will upgrade Thailand to become a developed nation," he said.

The project's first phase is set to include a 27-square-km industrial estate and will begin with construction of a 138-km (86 mile) road from Dawei to Kanchanaburi province, 119 km northwest of Bangkok.

Italian Thai Development Pcl and Rojana Industrial Park will have the rights to develop the first phase of the project.

The Dawei Special Economic Zone project has been stalled for years.