Beijing city authorities are trying to attract foreign investment in a 30 billion yuan (about HK$28.1 billion) project to expand its metro capacity to ease the worsening traffic congestion.
The project aims to add one railway linking the municipality's subway to the Beijing Capital Airport and two other extension lines within the city.
Executive deputy director Guo Junqing of the city's development planning commission said the relevant authorities were in talks with Hong Kong conglomerates over investment in the metro. He declined to reveal names but said some had been long-time investors in Beijing.
The government set the metro expansion as a key task in the Tenth Five-Year Plan, aiming to expand the subway to 150 kilometres from 50 kilometres.
Mr Guo said the government had recently worked out favourable new policies to foreign investment in infrastructure.
Investors will be compensated for extra spending on a project above their tender construction price but below the price stated by the relevant authorities.