An evacuation notice has been served on a block of flats by landlords as a town centre building is in danger of collapse.
Highways officials have sealed off the centre of Tyldesley as the Marklands Building at the corner of Stanley Street and Elliot Street has been affected.
Fourteen flats in the four-storey complex, above street level, have been affected.
Damage appears to have centred on a section of the first floor, just above the roof line of a branch of Balmers Wilcock, which occupies the ground floor.
Council officials say that a diversion has been in place to take traffic away from Elliot Street, Chapel Street and Stanley Street.
The V1 and V2 bus routes, which use the guided busway nearby, are also said to have been temporarily affected.