Cambodia is engaged in destructive sand exports to fuel Singapore's rapid expansion despite a supposed government ban on the practice, an environmental watchdog said Tuesday. London-based Global Witness said Cambodia was making a 'mockery of the government's supposed May 2009 ban on sand-dredging', risking devastation to its coasts, endangered species, fish stocks and local livelihoods. 'There is no evidence that basic environmental safeguards have been applied, with boats reportedly turning up and dredging sand, often in protected areas, with no local consultation,' said its new report, entitled 'Shifting Sands'. The group, which has made many allegations of Cambodian cronyism in recent years, said Mong Reththy and Ly Yong Phat -- senators known to have close ties to premier Hun Sen -- have been covertly awarded licences to dredge sand. 'This situation highlights the continued failure of Cambodia's international donors to use their leverage to hold the small elite surrounding the prime minister to account,' said George Boden, campaigner at Global Witness. The report said investigators tracked sand-filled boats from Cambodia to Singapore, estimating concessions from southwestern Koh Kong province alone netted 20 million dollars per month for some 796,000 tonnes of sand. Global Witness added that figures from other concessions along Cambodia's coast were not known, and there was no way to track whether revenues from sand exports reached the national treasury. 'In addition, Global Witness has seen Cambodian sand dredging and export licences which bear the stamp and signature of a representative of the Singapore Embassy in Cambodia,' the report said. Singapore has expanded its surface area by 22 percent since the 1960s, said the report, requiring vast quantities of imported sand from neighbours in Southeast Asia. Indonesia, Malaysia and Vietnam have halted sand exports to the city-state over concerns the practice depleted fish stocks and caused erosion. The Cambodian government has banned past reports by Global Witness, which also accused donors of ignoring graft among elites who have allegedly been involved in illegal logging as well as shady oil and mining deals. 