From 6pm on Tuesday, April 21, until 9am on Friday, April 24, a number of car parking spaces will be blocked off to enable scheduled maintenance works.
Mersey and West Lancashire Teaching Hospitals NHS Trust has issued an apology for the inconvenience caused.
The trust said: “A number of car parking spaces will be blocked off to enable scheduled maintenance works to the Whiston Hospital A&E car park.
“We apologise for any inconvenience caused.”
The trust has not specified how many spaces will be affected during the works.
There is a free shuttle bus service offering transport between Whiston Hospital and St Helens Hospital.
It runs every 20 minutes on Monday to Friday, between 7:20am and 6:10pm, and picks people up at the main entrance of each hospital.
Alternatively, if using public transport, bus routes 89, 10A, and 61 drop off outside Whiston Hospital.