The public have been warned to avoid “risky activities” as ambulance drivers stage strike action.

Health minister Will Quince urged people to stay safe on Wednesday, which will likely see the NHS hit by major disruption as ambulance workers including paramedics, control room workers and technicians walk out in England and Wales.

During the strike, the military will not drive ambulances on blue lights for the most serious calls but are expected to provide support on other calls.

The junior minister said that armed forces personnel would play a key role but would not be able to “break the law” when covering for ambulance workers.

Mr Quince urged the public to avoid anything risky on Wednesday, telling BBC Breakfast: “Where people are planning any risky activity, I would strongly encourage them not to do so because there will be disruption on the day.”

The health minister did not offer examples of what might be defined as risky behaviour but told the public that in any emergency calling 999 should still be the first option.

“But the key thing is for anybody that does have an emergency situation or a life-threatening situation that they continue to call 999 as they would have done previously, and for any other situation, NHS 111 or NHS 111 online.”

Later on BBC Radio 4, he also said that anyone with chest pains on Wednesday should still call 999.

Downing Street later declined to set out what “risky” activities might include, with the prime minister’s official spokesman telling reporters: “The public, as we saw through Covid, can be trusted to use their common sense.”

Negotiations between unions and ambulance services are ongoing to work out which incidents should be exempt from strike action.

It is expected that all category 1 calls, the most life-threatening such as cardiac arrest, will be responded to.

Some ambulance trusts have agreed exemptions with unions for specific incidents within so-called category 2 which covers serious conditions, such as stroke or chest pain.