North Bank, Whittlesey is closed between the former Dog in a Doublet pub and Northey Road/Storeys Bar Road as police hunt for a missing man.
The man left work in Fengate, Peterborough, on Tuesday evening and has not been seen since.
Police have urged drivers to find alternative routes.
One person said the police have been seen in boats on the river earlier in the day hunting for the missing man and his car. This has not been confirmed by police.
CambsNews has decided not to share any detail of the social media appeal for the missing man until Cambridgeshire police release an official statement.
