More than 170 people could have contracted E coli in an outbreak linked to a restaurant in north Belfast, health authorities in Northern Ireland have said.

There are 20 confirmed and 150 probable cases to date, the Public Health Agency (PHA) announced in its latest update on the food poisoning crisis.

The agency said it expected more instances to emerge in the coming days.

The diners were struck down after eating at Flicks in Cityside Mall, York Street, in the last three weeks.

Six of the people with confirmed E coli had to be hospitalised, although the majority have since been discharged, the PHA said.

Management at the restaurant have voluntarily closed the premises and are co-operating with an investigation by the PHA and environmental health officers from Belfast City Council.

The PHA has advised that anyone who ate at Flicks since 24 September and has symptoms of diarrhoea and/or abdominal pain should contact their GP urgently for medical advice.

The combined number of confirmed and probable cases has more than doubled since the PHA issued an update yesterday.

Dr Michael Devine, Consultant in Health Protection at the PHA, said the increase was not unusual.

"The further increase in cases is not unexpected as the incubation period for E coli is typically up to seven days," he explained.

"We expect therefore to see a further increase in cases as people continue to report symptoms and submit samples for testing."

The agency revealed yesterday that four cases of the same E coli O157 strain were linked to the restaurant in August.

But it said subsequent tests in the restaurant at that time were negative.

Further environmental health inspections were conducted after those incidents, all of which were satisfactory.

The PHA said enhanced surveillance to monitor for cases was also put in place and the current cases came to light through that system.

The agency has said it was examining whether the current outbreak was linked to the August instances, but it was too early to confirm either way.