However, such sums are only a tiny fraction of the wealth of the owner of Australia's Nine television network, estimated to be around $8bn.
The media magnate, who is known as one of the world's biggest gamblers, lost the money at his favourite card game, baccarat, at the Bellagio hotel, the Australian newspaper reported, citing casino sources.
"By the end of that Friday (14 July), he was already down between US$17 million and US$20 million and then coming out of the weekend, he didn't recover," a source told the newspaper.
Mr Packer is said to head a list of 150 "whales", high-rollers who are entertained lavishly at casinos in recognition of their habit of putting up - and sometimes losing - hundreds of thousands of dollars a day on gambling.
Drop in the ocean
Mr Packer was also reported to have suffered the biggest losses ever sustained in the UK in September 1999, dropping £11m ($16.5m) at Crockfords casino in London.
However, such sums are only a tiny fraction of the wealth of the owner of Australia's Nine television network, estimated to be around $8bn.
In spite of his occasional losses, Mr Packer has been banned from some casinos as a "hit-and-run gambler" - leaving establishments after a quick, big win and not allowing the house to win back its money.
One of these was Las Vegas' MGM Grand, after he won $26 million playing blackjack for $200,000 a hand, six hands at a time.
Legendary status
Howerver, there are also tales of incredible generosity, including a $100,000 tips to dealers and waitresses and loans to fellow gamblers whose repayment he refuses to accept.
Legend has it that Mr Packer's grandfather put the family on the road to riches by buying a passage from Tasmania to the mainland on the proceeds of a bet on a horse. He found his 10 shilling stake lying in the street.
To this day Mr Packer is said to enjoy the unusual characteristic among gamblers of winning more than he loses.
After the Crockford's losses, a friend was quoted as saying: "Kerry probably will not mind too much. It is probably the casino's money anyway."
It is said that only the Sultan of Brunei and Adnan Kharshoggi, the Arab arms dealer, can match Mr Packer's legendary status as a high stakes gambler.