The dazzling choices available today are a marked contrast to the simple origins of lai see packets. According to legend, the custom of giving an auspicious red-coloured item during the Lunar New Year began as a way to ward off the nian, a monster that emerged to attack villages each spring.

The tradition spread during the Qing dynasty, when lai see took the form of coins tied up with red string, which were placed under pillows on the eve of the festival for protection. Over time, people began wrapping money with red paper and adults would give the red packets to younger family members as a blessing.

'The more lai see you give away, the luckier you are,' says Maria Tam Siu-mi, an associate professor of anthropology at Chinese University. 'The logic is simply that you have to be extra lucky to be able to share with others.'

Customarily, married couples would give lai see to single people, regardless of any age difference. For example, a married niece will give lai see to her uncle if he's still a bachelor. But Tam finds fewer people are giving lai see today, especially the younger generation.

'Instead of giving each other lai see, young people tend to give them to their children, or not at all. They believe it's fairer,' she says.

Still, entrepreneurs such as Ng are survivors. Her company was among the many businesses forced out of Lee Tung Street - better known as Wedding Card Street for its wedding card printers - for redevelopment. She has since set up her operation in a Wong Chuk Hang industrial building, and opens temporary outlets such as the current shop in Causeway Bay during festive periods.

At Man Fat Company in Yau Ma Tei, owner Tsui Koon and his family have been producing packets the old-fashioned way for nearly half a century in their Shanghai Street print shop.

The 77-year-old is particularly proud of a pair of German gilding machines he acquired 30 years ago.

'These machines have never let me down. I hardly have to spend anything on maintenance,' he says.

Keen to demonstrate the process, he places a stack of plain red envelopes onto a frame that holds them in place and turns on the power. After pressing a lever, gold foil is sent to a heated zinc plate that melts the film to print selected motifs on the envelopes.

Tsui concedes that Man Fat is an outmoded operation. 'Many lai see shops outsource their printing to factories on the mainland, but as long as my machines still work, I don't see why I should replace them,' he says. They make such a racket that Tsui and Sin-fai, his 47-year-old son, can barely hear each other speak above the noise.

The packets feature typically auspicious symbols such as eagles (to signify a promising future), signs of the Chinese zodiac as well as surnames. Over the years, Tsui has accumulated more than 100 printing plates, many of them featuring old-style designs that are no longer available elsewhere.

'Although people's tastes continue to change with time, lucky symbols still remain a firm favourite,' he says.

History and design buffs keen to trace how the traditional red envelope has evolved over time should take a look at Guangzhou sales assistant Chen Haiping's collection of 40,000 packets, some more than a century old.

The 51-year-old, who was recently in town for an exhibition of his samples at a Tsing Yi mall, says his hobby is more than a pastime.

'It helps me get a better idea of the culture of the time,' he says. 'You can see the history from the design; some were issued by restaurants, banks or jewellery shops that no longer exist today and the lai see packets bearing their names, addresses and phone numbers are the only legacy.'

One packet from the 1920s, for example, features a delicate woodblock print portrait of a government official, who signed his name on the back of the bamboo-paper envelope.

But Chen says he doesn't spend his time scouring antique markets for such items. 'I often pick up packets discarded by others on the street. I take them home, brush them clean then iron them and store them in plastic bags.'

Indeed, his favourite item is an accidental find: a handmade envelope dating back to 1904 and found between the pages of a book he bought at a second-hand shop. Made with plain red paper, it bears the name of the issuer, Tung Shan Match Factory, and is only large enough to hold a couple of coins.

Young designers such as Dorophy Tang Cheuk-yuet, however, reckon the way to keep the lai see tradition alive is by giving the envelopes a more trendy look.

The packets she created for a local mall this year, for example, feature chubby-faced babies in tiger costumes. And besides the usual auspicious symbols, the 25-year-old has the babies hugging doughnuts and heart-shaped chocolates, as Lunar New Year coincides with Valentine's Day this year.

'I used a lot of colours, so people can anticipate a sweet and happy year ahead,' says Tang.

'Young people today are looking for fresh ideas because they are knowledgeable and aware of different designs. I think the way to preserve tradition is to revamp it to attract younger people.'

Ng, too, keeps a close eye out for what appeals to the new generation of customers. Some might assume that they prefer self-sealing lai see packets (a relatively new invention), but she says most now choose lai see envelopes without glue flaps.

An enterprising sort, Ng designed the purple lai see packets that are her top sellers. These are a favourite with tai-tais and young fashionistas, she says, along with packets embossed with the sender's surname on the front, and oversized packets made with gold foil, which some people tear up and place under their pillows for good luck.

'People are willing to try something different; in fact they love surprises. It's a once-a-year tradition, so people want to impress their family and friends.'

Some customers spend several thousand dollars on lai see packets, Ng says. With hers priced at between HK$50 and HK$160 for 100, that's an impressive amount of lai see - and good fortune.