Wrightington Wigan and Leigh NHS Foundation Trust bosses say that the 52-bed facility should be up and running by the end of the month.
A large crane was brought onto the hospital site on Thursday afternoon and from 10pm onwards has been lifted components of the medical facility from off the backs of HGVs parked on Wigan Lane.
WWL chiefs have warned that there will be traffic disruption until around 7pm on Friday.
