A construction company has been fined $322,000 for mosquito breeding, rat infestation and construction noise offences.

Sunhuan Construction, which committed the offences between July 2014 and February this year, was fined on Tuesday.

A series of inspections led to the discovery of mosquito breeding in five of the firm's construction sites, as well as rat droppings at one of the sites. Four of the firm's construction sites were also issued with stop work orders, due to poor work conditions.

The company faced 13 charges under the Control of Vectors and Pesticides Act and three charges under the Environmental Protection and Management Act.

It also committed noise offences by allowing construction works to take place on one of its sites on a Sunday on three occasions.

This violates the National Environment Agency's (NEA) no-work rule, which prohibits work on Sundays and public holidays at constructions sites that are within 150m of residential and noise sensitive premises.

In a statement on yesterday, the NEA said it is focusing on checking areas that have higher potential for dengue transmission, with the help of the Singapore Contractors Association and industry leaders.

Mosquito breeding at construction sites has decreased from 11 per cent in 2013 to 6 per cent this year, as at June 2017, said NEA.

The agency urged construction companies to educate and protect their workers against dengue by encouraging good housekeeping practices, such as removing food sources, and also carrying out routine pest control.