Staff and patients at the borough's hospitals face another day of disruption as work continues to resolve a system breakdown.
Wrightington, Wigan and Leigh NHS Foundation Trust, whose sites include Wigan and Leigh infirmaries and Wrightington Hospital, was hit with major problems yesterday.
There were issues with storing and viewing diagnostic images in radiology departments, including X-ray, CT and MRI scans, and with the IT infrastructure across all sites.
It meant that patients taken to the A&E unit after emergency 999 calls were transferred elsewhere once stablised and all non-urgent or planned outpatient appointments requiring diagnostics were cancelled "until further notice".
It is understood the Thomas Linacre Centre was closed for some time on Wednesday, but later reopened.
The trust hoped the problems would be resolved by noon on Thursday, but it is now expected to take longer to fix the issue.
A trust spokesman said: "We would like to reassure our patients that our IT department are working extremely hard to address the situation and hope to have a solution by close of play today.
"We would also like to thank all our staff during this period of disruption, we appreciate all their continued hard work during this time to ensure patient safety remains paramount
"We have been working from our business continuity plans since 9.30am yesterday morning, this continued overnight and will continue until we are confident the measures that we are putting into place have been successful.
"We are repeating our previous advice and asking patients who need urgent health advice are advised to visit their local pharmacy or contact NHS 111 by phone or online at 111.nhs.uk."