More than 40 people have been confirmed as contracting a potentially lethal strain of E coli, Northern Ireland health authorities have said.

In its latest update on the food poisoning crisis the Public Health Agency said there could be a further 144 cases linked to a north Belfast restaurant.

"As of 3pm today there were 44 confirmed cases and 144 probable cases," a spokesman said.

The outbreak, which has been linked to Flicks restaurant in the Cityside Mall complex, has been described as the worst ever seen in Northern Ireland.

Since the start of 15 October people have been hospitalised with E coli however, the majority have since been discharged.

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.

In a statement the PHA said it was still trying to determine the cause of the outbreak.

"Investigations are continuing and final conclusions will emerge when all cases have been identified and analysed to identify any common links," the PHA said.

Yesterday the PHA said the strain of E coli found in October was not the same as a strain linked to four cases connected to Flicks in August.

"There are various types of E coli O157 and the PHA has confirmed that the type of E coli O157 in cases in October is different from the type found in August cases associated with the same restaurant.

"These results are from a first phase of typing tests which showed the cases in August to be Type 8. The confirmed cases in October are Type 54.

It is too early to draw definitive conclusions at this stage," the PHA added.

Director of public health Dr Carolyn Harper, PHA, said: "The PHA has activated a full public health response to this outbreak and the situation is being managed and monitored very closely."

She said: "It is vital that everyone follows some simple rules to prevent the spread of E coli - not just those with symptoms, but everyone should wash their hands after using the toilet and before eating or preparing food.

Dr Harper advised: "Raw and cooked food should be kept completely separate, raw meat should be cooked through and vegetables and fruit should be washed thoroughly before eating."