Emergency services including an air ambulance were called to the Wild Duck park in Belton near Great Yarmouth.

The incident started at one of two swimming pools at the site.

A Norfolk Police statement said the pool had now been declared safe.

"The immediate area was evacuated and a 20 metre cordon put in place," the statement said.

Haven Holidays spokesman Tom Cassidy earlier said those treated included a three-year-old child.

"There was a chemical leak in the swimming pool in the entertainment complex and it was evacuated while police and fire and rescue were on their way.

"The casualties have been described to me as walking wounded. Obviously the park is now in lockdown while they try and source the chemical leak."

Operations Manager Ian Pennell says they've tried to help all those involved.