City clerk Khunying Nathanon Thavisin said yesterday she would sign a Bt3.87-billion contract, on behalf of the Bangkok Metropol-itan Administration, with Italian-Thai Development Plc to build the civil works - stations and tracks - for the 5.25-kilometre extension.

The project's total cost exceeds Bt8 billion: Bt3.873 billion for civil engineering, Bt4.65 billion for signalling and operation systems, Bt245 million for consultants, and Bt10 million for public relations.

The extension will have stations at Sukhumvit 83, Sukhumvit 97/1, Sukhumvit 101/1, Sukhumvit 101/2 and Sukhumvit 107 (Soi Baring).

The Bangkok Council has only approved a Bt719.2 million budget for the project so far.

But BMA Traffic and Transport Department director Apirat Siwa-pornpitak said Ital-Thai would start the first phase next month, moving infrastructure such as electric and telephone wires and water pipes to make way for the construction of station bases and tracks.

The extension is due to be finished in three years, he said.

The contract-signing will be held at City Hall.