The government has estimated that the construction cost of the MTR's Tung Chung Line extension will be almost HK$19 billion.
The HK$18.7 billion price tag, based on December 2016 prices, will be used to build two new stations on the existing Tung Chung Line.
One of the new stations, Tung Chung East, will be located between Sunny Bay and Tung Chung stations, while the other, Tung Chung West, will be on a 1.3-kilometre track extending from the current terminus at Tung Chung.
Construction of the stations are expected to begin in 2023 and take six years.
In a paper to Legco, the government said the project would support a development plan in Tung Chung which is one of the important, medium-to-long term sources of land supply to meet Hong Kong's economic, social and housing needs.
Starting from 2024, the first batch of 31,000 public housing residents are expected to move in to the new homes – with the goal of accommodating 126,000 people when the entire project is completed in 2029.
The government is asking the MTR Corporation to proceed with a detailed planning and design for the extension, and said it will negotiate with the rail company on the funding arrangement.