Despite former prime minister H.D. Deve Gowda's objections to the proposed Bangalore Metro, work on the project is expected to take off next month, sources in the Prime Minister's Office (PMO) said.

"Work on the Metro project is likely to start next month," the source said.

In a letter to Prime Minister Manmohan Singh, Gowda, whose Janata Dal-Secular (JD-S) is ruling Karnataka in coalition with the Congress, asked for a review of the Rs.60-billion project, describing it as "ruinously expensive".

But the PMO source said: "Any further delay will only prove costly. It cannot be scrapped."

Gowda had suggested "cheaper and less intrusive" transport systems to ease Bangalore's traffic, such as light rail system and monorail, especially the hybrid monorail.

He argued that both the central and state governments should have a re-look at the Metro project.

The Congress and the JD-S in Karnataka appeared to be on a collision course by singing different tunes on the ambitious Metro project.

Congress legislators representing city constituencies strongly supported the project, arguing that it was an ideal mass transport system to decongest choked roads.

Even Bharatiya Janata Party (BJP) legislators from the city contended that any move to scuttle the Metro project would only "regress" Bangalore's transport system by 20 years.

Chief Minister N. Dharam Singh has ruled out scrapping the project. A team of the Japan Bank for International Corporation, an external funding agency, is in Bangalore to review the project.