City of Sydney will double the number of rat baits on council-owned land after an increase in rat sightings which the council says is a result of the unprecedented number of major construction and infrastructure projects.

Several cases of leptospirosis in dogs have also raised concerns.

"We have been very concerned about the recent cases of leptospirosis in Sydney affecting dogs in our local area," Lord Mayor Clover Moore said in a statement on Monday.

Leptospirosis is a disease caused by bacteria found in infected animal urine and tissues.

More than 850 rat baits will be put in public areas to monitor rat activity and additional baits will be put out when the council receives complaints from residents and businesses.

The council has urged Sydney Trains, Property NSW, Sydney Water and NSW Land and Housing to increase baiting and inspections on their own land.

"We can't fight the rat problem on our own because we can only install rat baits on our own land," Ms Moore said.

Residents and businesses have also been urged to take care with food scraps and waste and to ensure regular pest control is carried out on private properties.

Australian Associated Press