Four people have been taken to hospital with burns after being struck by lightning in Sydney’s botanic gardens.

A spokesperson for New South Wales Ambulance said the quartet was standing underneath a tree when struck at about 12.45pm on Monday.

Multiple crews treated the patients including a teenage boy, a woman in her 20s and a man and woman both in their 30s.

The four were “knocked unconscious” when struck by the lightning but regained consciousness shortly afterwards, the ambulance spokesperson said.

Whether the injuries were sustained from a direct lightning strike or from being under the tree when it was hit remained “unclear at this point”, the spokesperson said.

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The teenager and the woman in her 20s were taken to the Royal Prince Alfred hospital where they remained in a stable condition. The older man and woman were taken to St Vincent’s hospital.

The four patients sustained “some burns” from the lightning. They were being monitored for cardiac issues.

Transport for NSW later on Monday afternoon said the severe weather had affected train equipment at North Sydney with no trains running between that station and Gordon.

Passengers were told to avoid or delay trips on the T1 North Shore line and that replacement buses would be in service.

On Monday afternoon, there had been about 75,000 lightning strikes detected within a 100km radius of Sydney, Weatherzone’s meteorologist Ben Domensino reported.

The NSW State Emergency Service (SES) urged people in the eastern parts of the state to stay across weather warnings amid severe thunderstorms and heavy rain forecasts, which could bring on flash flooding in low-lying areas.

People in Sydney, the Blue Mountains, the Central Coast, the Hunter and on the mid north coast should monitor conditions over the next few hours, the SES said.

Areas such as Taree, Newcastle, Penrith and Armidale could also be affected by heavy rain.

The NSW SES assistant commissioner Sean Kearns said there was potential for isolated heavy falls of 50 to 100mm.

“The NSW SES has prepositioned personnel throughout the region, and we are well-resourced to respond to any calls for assistance,” Kearns said.

“I would encourage the public to follow the advice of emergency service personnel on the ground and not to drive through flood water.”

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