Macau's highest court sentenced a former minister to 29 years in jail on Thursday over a multi-million-dollar corruption scandal involving the biggest graft investigation in the gaming hub's history.

The Court of Final Appeal found former transport and public works minister Ao Man-long, who is already serving a lengthy jail sentence for other offences, guilty of nine counts, according to the 108-page written judgement.

The panel of three judges convicting him on three counts of money laundering and six counts of bribe-taking, and sentenced him to a fine of 240,000 patacas ($30,000) on top of his jail term.

"The bribery acts of the defendant are most shocking given his high-ranking position in Macau's administration, as well as the huge amount of sums involved," the judgement said.

"His acts have cast Macau's government and its civil service in a very negative light," the judges said, adding that the 55-year-old failed to show any remorse during his testimony.

Ao is currently serving a 28-and-a-half-year jail term after being convicted in 2008 and 2009 of taking payments from contractors in return for approving either land sales or major construction projects in Macau.

A Macau government official told AFP that the sentences would run concurrently.

The trial heard that Ao received HK$20 million ($2.6 million) from two Hong Kong tycoons for the acquisition of land on which a HK$20 billion luxury residential project was being built.

Thursday's verdict also cast a spotlight on the two Hong Kong tycoons, Joseph Lau and Steven Lo, who have both been charged with bribery and money laundering in connection with the case.

Lau, chief executive of property firm Chinese Estates Holdings, has denied he attempted to bribe Ao over the land tender in the case -- the latest corruption scandal to hit Hong Kong's business elite.

Lau, 61, is ranked fifth on Forbes magazine's list of richest people in Hong Kong, Asia's financial hub, with a fortune estimated at $6.5 billion.

Ao, who was in office between 1999 and 2006, was first arrested in December 2006 by the Macau Commission Against Corruption, and convicted on 57 counts of corruption, money-laundering and bribe-taking in January 2008.

He was sentenced to 27 years in the first trial and received another sentence of 28-and-a-half years in the second corruption trial in April 2009.

Ao had amassed a personal fortune of more than $100 million in his seven years in office -- 57 times his family's income during that time.

The case has cast a shadow over the former Portuguese colony, which lies just one hour away by ferry from Hong Kong and has struggled to shake of its "Sin City" image despite attracting huge amounts of foreign investment.

Macau, which was returned to Beijing in 1999, has boomed since its gaming sector was opened to foreign competition in 2002 and now generates five times the gambling revenue of Las Vegas, thanks mainly to high-rolling Chinese VIPs.

Macau is the only place in China where casinos are legal.