The Environmental Protection Department has rated water quality at 24 beaches 'good', eight 'fair', and one 'poor' for this weekend.

Compared with the grading released last week, Ma Wan Tung Wan Beach has been downgraded from 'fair' to 'poor'.

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.