About 100 private tutorial schools have been reported this academic year for running courses without a licence. Four schools are being prosecuted and others investigated in an attempt by the Education Department to stop unregistered institutions wooing students. The Examinations Authority is reminding students to beware of private tutorial centres which claim to have hired its officers or have leaked exam information from the authority. This year about 30,000 candidates will sit for the Advanced-Level examinations and 115,000 candidates will take the Hong Kong Certificate of Education Examination. Tests in major A-level examination subjects including Chinese Language and Culture and Use of English take place this week while mathematics, English and Chinese languages will begin next month. The Education Department said students should check that a school had been registered with it. Under the existing education ordinance, any establishment which provides lessons for 20 or more people during any one day, or eight or more people at any time, must register with the department. Yu Law Siu-man, the department's senior education officer, said they received reports of 88 cases of unregistered schools from September to March. She said about 270 inspections had been made and 94 warning letters issued to those institutions this school year, compared with 200 inspections made and 19 warnings issued throughout last academic year. A simplified procedure had helped, she said. 'In the past, we had to pay two fact-finding visits, one confirmatory visit and issue two warning letters before we could consider taking legal action against a school,' she said. 'But under new rules we only have to visit the school once and issue one warning before we can prosecute it.' She said the standard of unregistered schools had no guarantees and students should not sign up for their courses. Unregistered schools face a maximum fine of $25,000.