Warning letters are to be sent to employers who place advertisements in newspapers and on Web sites that do not identify their companies, Privacy Commissioner Lau Ka-men has announced. Mr Lau said the adverts breached the Personal Data (Privacy) Ordinance under a new code of practice on human resources management, effective from April 1. If convicted, the maximum penalty is a $50,000 fine and two years in prison. Mr Lau said the 'blind' advertisements were still found in newspapers. A team has been set up within the commission to hunt them out. About 1,500 letters have already been sent to employers who had placed such notices two weeks before the law went into effect. Mr Lau said the commission had received a large number of inquiries about the new rules. 'The protection of personal data is a cultural change. And this will take a bit of time for people to change their concepts,' he said. He said the commission had held meetings with local newspapers and online job-hunting companies, asking them to co-operate with the new law by telling their clients about the changes. The new rules require all employers to identify themselves in job advertisements. They also allow staff to see their personal files and to correct inaccurate information. The move prevents employers from collecting excessive personal data on job applicants. Employers can only seek references from candidates' past employers with their consent. However, employers and head-hunting firms which advertise on companies' behalf have expressed concern the changes will reveal staff turnover and affect morale. They said that sometimes they did not want other companies to know that they were hunting for certain kinds of employees.