
The traders are promised a 7-year jail term and a fine of 140,000.
Commerce Permanent Secretary Yanyong Phuangrach said that the product prices should not be raised as manufacturing costs stay the same.
The ministry's hotline 1569 has received complaints on such irregular price increases.
To complaints over an irregular increase in sand, Yanyong noted that it should be retailed at Bt450 per cubic metre. Meanwhile, empty sand bags should be retailed at Bt3 for the 25cm size and Bt7 for the 50cm size.
Some sand traders are reportedly jacking up the prices, as sand is in high demand in Bangkok as residents try all means to prevent their residences from floods.