A shortage of granite due to an Indonesian export ban has left several construction projects in Singapore in a rocky state.
Contractors told The Straits Times that there have been delays for various projects since the middle of this month.
A Building and Construction Authority spokesman said yesterday that the industry was still importing granite aggregate from "many other regional sources", though it declined to name them. She said it was working with importers to ramp up supply from these "diversified" sources.
"If needed, the Government will activate the release of the national stockpile to ease the temporary disruption in supply," she added.
Granite aggregate is hard stones crushed into small pieces, and is different from granite slabs.
Indonesia, South-east Asia's biggest economy, is a major supplier of granite aggregate to Singapore. It is a crucial component of ready-mixed concrete.
The Indonesian government banned a wide range of minerals from being exported globally on Jan 12.
It stopped shipping granite aggregate to Singapore around the same time.
It is understood that the regulations issued by the Indonesian government say that exports of raw or unprocessed granite out of Indonesia are not allowed. Only granite that has been shaped, cut or processed can be exported.
It is understood that there is no specific ban on shipping granite to Singapore.
Since Jan 10, no granite aggregate shipments have been allowed to be shipped from Indonesian jetties, said the Singapore Contractors Association last Friday.
"Many projects, both private and public, are affected by the disruption of supply," said association president Ho Nyok Yong.
Contractors told The Straits Times that the shortage was reminiscent of Indonesia's overnight ban on sand exports in February 2007, which sparked a "sand crisis". Sand is also a vital ingredient in concrete.
Indonesia also later that month detained a number of barges that were carrying granite to Singapore on suspicion of smuggling sand. This disrupted granite supplies although it was not banned at that time.
Contractors said Malaysia and Vietnam also supply granite.
They noted that the supply disruption has made the biggest dent in projects that had just started or were midway through construction.
"We would have liked to speed up," said Mr Kenneth Siew, general manager of Expand Construction, which is building Housing Board projects in Sembawang and Punggol.
"It would have been worse if it was not Chinese New Year, because (now) we slow down anyway."
Construction at the Sembawang project is now progressing at a third of the original pace or even slower.
Mr Siew added that the situation was worse at a Punggol East project that is midway through construction.
The project has eight cranes costing $20,000 a month each to rent, so a one-month delay can send $160,000 down the drain, Mr Siew said.
Ms Karen Lee, general manager of Hi-Tek Construction, said that the disruption could trigger a delay in a new HDB development that the firm was supposed to begin next month in Sembawang.
Indonesia's ban of raw material exports globally was first unveiled in 2009 amid a commodities boom.