The Environmental Protection Department has rated water quality at 23 beaches 'good', nine 'fair', and one 'poor' for this weekend.

Compared with the grading released last week, Silver Mine Bay Beach was downgraded from 'good' to 'fair'.

Seven gazetted beaches - Anglers' Beach, Approach Beach, Ting Kau Beach, Casam Beach, Gemini Beaches, Hoi Mei Wan Beach and Lido Beach - are closed to swimmers year round because of poor water quality.

Many beaches are likely to be more polluted than their grades suggest during and after periods of heavy rain. Bathers should avoid swimming at beaches for up to three days after a storm or heavy rainfall.

For updates on beach water quality, see the department's website, or call the beach hotline 2511 6666.