Property agent Zhao Xu runs a successful side gig selling medicines and cosmetics from Japan.

In a good month, she can make between 4,000 and 5,000 yuan (S$807 and S$1,000), which equals about a third of her pay cheque from her full-time job.

And all it requires is just a mobile phone, Internet access and Wechat, an instant messaging app.

"We are selling to our friends or friends of friends, so there's higher credibility here compared to shopping on Taobao, where people are buying from strangers," said the 27-year-old Beijing resident.

She notes that Taobao, an established consumer-to-consumer e-commerce platform, has suffered from negative publicity due to the prevalence of counterfeit goods.

The advent of the Internet economy has made it easier for many digitally savvy Chinese like Ms Zhao to earn a few quick bucks on the side, tapping on the convenience of mobile platforms.

These new forms of work and business opportunities afforded by the Internet, especially mobile Internet, come as China restructures its economy from an investment and export-led growth model to a consumption-led one with a bigger emphasis on the services sector.

While opportunities for digital natives increase, jobs in the slowing manufacturing sector are being cut or relegated to short-term or part-time contracts.

Some factories in southern China have turned to hiring temporary workers by the day to cope with higher costs and unpredictable demand, reported Reuters.

Even so, four in 10 Chinese hold two jobs, according to a survey by human resource service provider 51job. Other than the "old" forms of part-time work such as retail sales, tutoring and cleaning, increasingly people are moonlighting as online personal shoppers or drivers for car-hailing firms like Uber and Didi Chuxing, said the survey.

"All I have to do is to send photos of the products to my circle of friends on Wechat," said Ms Zhao. "Those who are interested can instant message me and transfer payment to me all within the same app."

She then gets a former classmate who lives in Japan to source for these products and send them over. For every item she sells, she makes a profit of 30 yuan to 50 yuan. Yet, she can sell these items at a far lower price than in the shops here.

She has another advantage over brick-and-mortar stores. "Some people are sceptical about the products sold in the department stores, fearing that they may be fake," she said.

But to Ms Zhao, this will remain a side business that gives her some extra money for food and shopping.

"My company is aware of this, but I will make sure my bosses don't see the ads that I send out during office hours. I still value my full-time job as an agent," she said.

As for salesman Yang Ming, his job as a part-time personal driver brings him a substantial income - as much as the 2,000 yuan salary he earns in his regular job at an IT firm in Luoyang city, in western Henan province. He drives car owners home after they have had some drinks or help them take their cars to the workshops for servicing.

"All I have to do is to wait for an order to come in through my mobile phone," said Mr Yang, 30, who is on stand-by for potential jobs from 5pm to 12 midnight every day. "I get paid directly via the mobile app as well, so it's very convenient."

He is doing this "to pay for a house so that I can get married", he says, adding that moonlighting is common among his friends.

Renmin University labour expert Liu Erduo observes that the rise of the Internet economy has created opportunities for part-time work for many young people.

Other than personal shopping services, which are also known as weishang, or Wechat businesses, some are also providing copywriting services online, or even publishing novels, said Professor Liu.

"I welcome this new phenomenon, as it adds more depth to our services sector," he said. He added: "In principle, I think people should not allow such part-time jobs to affect their full-time employment. But I don't see any drawbacks for society as a whole."

He defended such part-time work, saying: "We shouldn't discredit the value that these part-time jobs can bring to our economy. Neither should we put a moral judgment on them."

Last month, a deputy township mayor in the central province of Anhui was investigated for moonlighting as a part-time driver for Didi Chuxing. It sparked debate on whether there was any wrongdoing, with many saying he was making an honest living on the side to supplement his 3,000 yuan income.

Prof Liu notes that China's working population has been declining since the end of 2011, and part-time jobs, especially those created by the Internet economy, can augment the labour supply and keep prices down.

Agreeing, Beijing-based economist Hu Xingdou said that these new opportunities allow people to have something to fall back on, reducing the risk of not being able to eke out a living amid a slowing economy.

"With a wider variety of work arrangements, people can have more options to earn money. Their incomes will rise, which will, in turn, boost consumption. This marks progress of our society," he said.

He noted that in the past everyone wanted to work for a major corporation. Then it shifted to freelance or home-based employment.

"Now in the Internet age, there are more options and more freedom for people to realise their personal value," he said.