The ICAC should investigate why Urban Services Department (USD) cleaning staff who slept and played cards during working hours were not exposed for more than a year, according to a report.
A Provisional Urban Council committee, which probed the case of lazy staff, said anti-graft officers should intervene.
Municipal councillors, acting on a tip-off, discovered the scandal in January.
Last year, the teams only transferred 0.32 tonnes of refuse a day. Since the scandal was uncovered, they have collected an average of 1.45 tonnes a day.
'The committee considers it was a group action. It is difficult to explain why such misconduct, which involved three groups of staff totalling 24 workers and some supervisory officers, could be covered up for more than a year,' a source said. 'It is impossible that no one in USD management noticed this. The committee considers it appropriate to probe whether corruption was involved.' It is understood the department strongly opposed the ruling, stressing workers' laziness was a matter of workplace culture and no corruption was involved.
But the committee, composed of six members from the Democratic Party, insisted on the wording.
The committee also condemned the department for not improving the workers' performance even though an internal report 14 years ago indicated a problem.