JAKARTA, March 13: Indonesia is considering a ban on granite exports, a report said on Tuesday, a move that could sour relations with nearby Singapore, given its use of the rock for construction.

Discussions about "the possibility of banning granite chips are taking place in the cabinet," Indonesia's Foreign Minister Hassan Wirayuda was quoted as saying by The Jakarta Post.

Ties between the two nations were already strained in January by an Indonesian ban on sand exports. The resource-poor city-state made heavy use of the sand to produce concrete to feed a construction boom.

Singapore has expressed disappointment at the sand ban and asked Indonesia to clarify whether it intends to impose a granite ban too.

Environmentalists have charged that sand mining, especially in Indonesia's Riau islands near Singapore, led to the extinction of several fish species and destroyed coral reefs.

Some of the smaller islands were also disappearing because of both sand and granite mining, Admiral Slamet Soebijanto, the head of the Indonesian navy, told the Detikcom news website.

Granite quarries had left gaping pits on the islands, he said, adding the environmental damage was "already serious."

"I will hinder and arrest anyone trying to take sand and granite out of Riau," he told Detikcom, saying such a move would be based on Indonesia's environmental laws.

Teams were studying environmental impact of granite mining on the islands, Agus Purnomo, a staffer at the environment ministry, told AFP. The department's minister said last week he was considering closing the mines.

Singapore has disputed Indonesia's claims of environmental damage and the crimping of its national boundary as the islands disappear.

There has been speculation that the dispute over sand and granite is intended to pressure Singapore into signing a bilateral extradition treaty, whose absence has soured relations between the two nations.

Jakarta considers such a treaty crucial to the fight against corruption and claims many suspects wanted in Indonesia have fled to Singapore.

Indonesia's vice president Jusuf Kalla, in a Financial Times interview last month, accused Singapore of refusing to sign a treaty because the city-state wanted to retain billions of dollars in allegedly corrupt money.

Singapore, a regional financial centre, says it has sufficient safeguards against becoming a magnet for laundered funds.—AFP