The North West Ambulance Service is currently dealing with a 'high number of calls'.
The service said today is a 'really busy today' for call handlers and crews.
People are being urged to only call 999 in a life-threatening emergency.
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A tweet posted on the official NWAS account at around 3.45pm today (Thursday) said: "It's another really busy day for our call handlers and crews so please help us to help you by only calling us back if the patient's condition worsens.
"We are currently answering a high number of calls.
"Please only call 999 in a life-threatening emergency.
"Use your pharmacist, GP or 111.nhs.uk in less urgent situations."
This comes after NWAS warned of delays on Monday as they dealt with a 'high number of incidents'.
The service said the high pressure meant that 'some people may wait longer for a response than we would like'.
The trust also warned that people won't be seen any quicker if they arrive to hospital in an ambulance, unless they are in a life-threatening condition.
