HONG KONG - Lunchtime traffic ground to a halt Wednesday on a busy road in Hong Kong's Wan Chai district after boxes containing more than HK$45 million in cash fell off an armoured cash escort vehicle. Police managed to recover HK$30 million and is appealing to the public for help to return HK$15 million in cash.

Local media reported that several drivers jumped out of their vehicles and joined passers-by in a mad dash to pick up the tens of thousands of notes scattered on Gloucester Road.

South China Morning Post said people were seen darting onto the road in an attempt to scoop up handfuls of loose HK$500 (S$85) banknotes.

Some managed to make a quick getaway before police armed with shotguns and wearing bullet-proof vests raced to the scene, and cordoned off two lanes of Gloucester Road.

Police superintendent Wan Siu Hong said all the missing banknotes were brand new and that his officers will try to find out the serial numbers to trace back the money.

No arrests have been made so far, and it was not yet clear what caused the boxes of banknotes to tumble out of the vehicle, reported broadcaster RTHK. There were 30 sealed boxes of cash in the van when the incident happened at around 1pm.

Investigators believed the seals on two of the three cash boxes were damaged in the fall, and bundles of banknotes spilled out from the boxes. Police managed to recover only HK$30 million out of the HK$45 million which fell out of the van.

Mr Wan called on anyone who picked up the money to hand it over to the police or risk being arrested for theft.

He also warned that people who took the money face up to 10 years in jail.

"I would like to take the opportunity to appeal to every member of the public that if they picked up any money to hand it over to any police officer or any police station as soon as possible," said Mr Wan.

"Our enquiry is still ongoing. We believe the money was dropped. We cannot rule out any possibilities at this moment."

One witness, an office worker at a nearby building who requested anonymity, told the South China Morning Post he saw a Hong Kong lady picking up at least 10 cash-bricks before walking off quickly.

"I saw a lady with 10 of them, easily. She looked like a very regular Hong Kong lady. She had an armful of bricks of cash - it was a much as she could carry. She just disappeared into the depths of Wan Chai," the witness was quoted as saying by the South China Morning Post.

The eyewitness said he had just left his office building when he noticed that traffic had ground to a halt.

"You couldn't make it up.There were 20 or 30 people picking up cash from the road on Christmas Eve. They looked like schoolkids who knew they were being naughty, but thought, 'this is a once in a lifetime thing'. Everyone had the same look on their face."

Pictures posted on social media showed a taxi driver stopping his vehicle in the middle of the busy dual carriageway to pick up money from the tarmac.

Representatives of the security firm G4S, which Apple Daily said was transporting HK$500 million in cash for Bank of China, were also at the scene.

Police officers were later seen counting notes recovered from the scene.