The incident, which came amidst a national spike in flu cases, was stood down on Monday after being declared on Saturday.
A Wirral University Teaching Hospital spokesperson said: ‘The trust experienced unprecedented demand for our urgent and emergency services last week resulting in a large number of patients requiring hospital admission, including a high number of flu cases.
‘To ensure we maintained patient safety, a critical incident was declared at the trust on Saturday. A robust plan of action was put in place and the incident was stood down on Monday.'
The trust said its Emergency Department remained busy and warned of longer waits while it prioritised urgent care. It urged people only to attend in the case of a genuine emergency.
A number of critical incidents have been declared by trusts in recent days as flu cases have quadrupled in England.