Their offer may look like the start of a glamorous career, but you have to be careful. Some of these scouts are real, others have bad intentions.
Some want models to pose for revealing photos, while others cheat unsuspecting girls. These crooks have made recruitment difficult for agents who are seriously looking for young models.
But there are still ways to identify real modelling agencies. Karen Cheung Wai-chi, a manager at A-class Model agency, says one simple method is to ask the agent to show a portfolio of the modelling jobs.
'If the agent claims their models do magazine shoots, for example, you can ask for copies of those magazines,' says Cheung.
'The photos are usually credited to the model agency, which can serve as proof of its identity.'
Cheung spent three years looking for part-time models for publicity events, shopping mall promotions and magazine shoots. She now leads a small team whose work includes picking potential models from the tens of thousands of pedestrians on busy streets.
Cheung says street hunting is only one of the methods they use because the success rate of finding the right person is not very high.
'The sharp rise in modelling scams in recent years has held most people back. Many just shake their heads and walk away as soon as I tell them who I am,' she says.
A more common and effective method is an open casting - a sort of audition for a large group of aspiring models.
'It's convenient for both the agency and people looking for modelling jobs. Applicants don't need to worry about safety because there are many others there, and the agency can select from a large pool of people,' she says.
Recruitment sessions at tertiary institutions, modelling contests and word-of-mouth searches are also effective, Cheung says.
Police recently found shady job advertisements on the internet aimed at young models. Fake agencies persuade youngsters to pay for "training" to boost their careers. Some victims have even been forced into illegal activities, such as drug trafficking and selling counterfeit goods.
Some agencies force girls to sign an agreement to buy beauty products or attend fitness sessions.
Cheung says genuine companies do not ask applicants to pay for training.
'We include the cost of training in our operating costs. If the agent asks you to sign up for an expensive course at the beginning, it must be a scam.'
Fake agents also want girls to make a quick decision and visit their offices immediately. 'Real model agencies are much less aggressive,' Cheung says. 'They'll do nothing more than give you their business card if you tell them you are not interested. Fake ones tell you repeatedly how perfect you'd be as a model, and encourage you to make a decision on the spot.'