Management and Approval Regulations for Hong Kong and Macao Residents with Overseas Compatriot Identity Article 6

When an employer hires the workers mentioned in Article 2, their maximum of working period is three years; If the employer needs to continue the employment after the contract ends, he or she must apply for an extension, with each extension being a maximum of three years.
中文原文 取得華僑身分香港澳門居民聘僱及管理辦法第6條
雇主聘僱第二條所定人員,其工作期間最長為三年;期滿後如有繼續聘僱之必要者,雇主應申請展延,展延每次以三年為限。
第四條第二項所定人員經許可工作者,其有效期間與許可居留期間同;居留期間屆滿,如有繼續工作之必要者,應於獲准延長居留後,向主管機關依第七條第二項規定申請許可。

English translation for reference only; the Chinese text prevails. Not legal advice.