Hong Kong  - Hong Kong's former head of civil engineering has been arrested over an alleged multi-million US dollar corruption case involving government highway contracts, a news report said Saturday.

Twenty people have been arrested for alleged corruption in the tendering of highway contracts in the former British colony, according to the city's Independent Commission Against Corruption.

Among those arrested, according to Saturday's South China Morning Post, is retired director of civil engineering Tsao Tak-kiang.

Tsao, 62, who has been decorated for his government service, is the most senior former or serving official arrested by the Hong Kong anti-corruption body, the newspaper said.

Investigators claim the highways department staff were bribed by construction companies to give out information about tenders for contracts worth tens of millions of US dollars.

The arrests took place after a senior government engineer was caught accepting an envelope containing more than 2,500 US dollars, according to the commission.

A chief government engineer, a senior engineer and three inspectors as well as nine subcontractors and four senior executives with construction companies are among the 20 arrested, a commission spokesman said.

All of the arrested people were released on bail Friday night without charge as investigations into the case continue, the spokesman said. (dpa)