A Christmas surprise ended in arrest for a Hong Kong beautician and a businessman who collected thousands of dollars spilled on to the street by careless bank security guards. The pair were tracked down by police, who found the money stashed under their bed.

They were taking a taxi along the city’s central Gloucester Road when boxes of HK$500 notes – each worth about £40 – fell out of a security van with a faulty door.

They stopped the car and began scooping up cash along with dozens of other delighted passersby, the South China Morning Post reported. People had grabbed up to $HK15m (£1.2m) by the time police arrived to seal off the area.

“At first people did nothing, then one person went into the road,” one witness who worked at a nearby office building told the newspaper.

“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.”

The guards from the security firm G4S did not notice their loss until they reached their base about eight miles away. The money belonged to the Bank of China.

“We found that something went wrong with the door on the left side,” said Sheeta Leung Hui-kwan, a spokesman for G4S Hong Kong. “Our guards [conducted] the job according to the standard procedure … Due to the code of conduct and comfort problems, we do not put any guards inside where we store the money.”

Photographs taken at the site of the spilled cash look like stills from a film, with banknotes scattered on the asphalt like rubbish and swirling around passing cars, while vehicles sit abandoned on the busy road as their owners scoop up the flying notes.

“The seal on two of the three plastic boxes was broken. They probably broke when they fell to the ground,” district police superintendent Wan Siu-Hong told Reuters. “They were all HK$500 banknotes, blocks and blocks of it.”

Anyone who thought they had stumbled across a Christmas windfall risked starting 2015 in jail, as police chased down those who made off with the notes. Police have appealed to anyone who picked up cash to hand it in, and warned that they will use CCTV footage to catch others.

“We will arrest as soon as possible all the people who have been identified,” said chief inspector Addy Li Chi-kin, adding that the couple arrested on Christmas Day had confessed.

“We found the money stored under the bed at their homes and they admitted they took the money after getting off the taxi they were in,” he said.

So far, about 30 people have given up HK$5m, and a poll on the South China Morning Post website found that nearly two-thirds of readers would not try to keep any notes if they had picked them up.

Legal experts said that people who kept the banknotes could be charged with larceny, which carries a sentence of up to 10 years in jail, AFP reported.