NEW DELHI - Indian billionaire Gautam Adani's joint venture with Mumbai's slum rehabilitation authority has hired a global team to redevelop Dharavi, a key step in rebuilding one of Asia's biggest slums amid growing opposition to the project.

Dharavi, about three quarters the size of New York's Central Park, is a crowded area that houses thousands of poor families in cramped quarters in the centre of India's financial capital. Many residents have no access to running water or clean toilets.

Rebuilding it is a mammoth task, which was first mooted in the 1980s.

The state government of Maharashtra in July approved Adani's $619 million bid to redevelop the area that covers 625 acres (253 hectares), and has been described by officials as "the world's largest urban renewal scheme".

The joint venture, Dharavi Redevelopment Project (DRPPL), said on Monday it was partnering with architect Hafeez Contractor who has done many social housing projects, U.S. design firm Sasaki, and consultancy firm Buro Happold from the UK for the redevelopment.

DRPPL was set up in July and hiring of the team assumes significance as it comes amid allegations from a rival bidder that Prime Minister Narendra Modi's allies afforded Adani favourable treatment while residents worry about his capacity to deliver amid high-profile financial setbacks.

The Adani group has said the Dharavi project was awarded through a fair, open and internationally competitive bidding process. The state government has denied any wrongdoing.

Thousands of protests marched toward Adani's offices in Mumbai last month to voice their opposition to his conglomerate's redevelopment plans.

(Writing by Tanvi Mehta; Editing by Alison Williams)