Christian groups and land-rights campaigners are petitioning the Hong Kong government to abandon a plan to develop artificial islands, saying it is unnecessary and could harm the environment.

Hong Kong chief executive Carrie Lam promised last month to boost the supply of land through reclamation and redevelopment, seeking to ease a chronic housing shortage.

The programme aims to develop artificial islands with a total area of about 4,200 acres in the next 20 to 30 years to house about 1.1 million people.

Opponents to the plan, including several Christian groups, say the plan - estimated to cost up to $64 billion – is wasteful and potentially harmful to the environment.

“The problem is ineffective land use, not lack of land. It is irresponsible of the government to consider reclamation before using existing resources better,” said Yip Po Lam of the Justice and Peace Commission of the Hong Kong Catholic Diocese.

“The reclamation process can hurt the ecology, and the islands would be more vulnerable to climate change impacts, including storms and rising sea levels. The money is better spent on social welfare schemes to benefit more people.”

Limited housing supply and large flows of capital from mainland Chinese buyers have pushed housing prices up 165 per cent over a decade in Hong Kong, one of the world’s most expensive property markets.

The city aims to increase the number of affordable flats by allocating more new land to public housing, including raising the ratio of public housing on newly developed land to 70 per cent from 60 per cent.

But analysts say it would take years for many of the government’s measures to increase the land supply.

The government must explore all brownfield options before considering any greenfield projects, said Keith Au at advocacy group Hong Kong Land Justice League.

“Reclamation will only benefit developers and businesses,” he told the Thomson Reuters Foundation.