SENIOR public health doctors are urging people not to panic after it was revealed that suspected cases of the Sars virus are being investigated in the region.

Dr Vivien Hollyoak, a specialist from Health Protection Agency North-East, said no probable cases of the Far East virus had been confirmed in the area.

"We can rest assured that we are in the fortunate position of having this under control in this country," said Dr Hollyoak.

At least 17 people are known to have been admitted to hospitals in the region with suspected Sars - Severe Acute Respiratory Syndrome - but Dr Hollyoak stressed that the tests were being carried out as a precautionary measure.

Last night, a spokeswoman for South Tees Hospitals NHS Trust confirmed that one suspected case has been tested and given the all clear at the Friarage Hospital, Northallerton, North Yorkshire.

Doctors at the trust are awaiting results on one other suspected case.

At North Tees and Hartlepool NHS Trust, doctors have carried out tests on a suspected case, which proved negative.

Doctors at Newcastle General Hospital said they had tested at least a dozen suspected cases. Two women, a 52-year-old and a woman in her 40s, who have returned from Hong Kong complaining of flu-like symptoms, are being kept in isolation there.

However, infectious diseases specialist Dr Ed Ong stressed it was "highly unlikely" they had the virus.

Sars, believed to be linked to the common cold, has been spread through air travel, with most cases in Asia. More than 130 people have died from the virus worldwide, with about 3,000 infected.

So far, six probable British Sars cases have been identified. Four have recovered, a fifth person is in a stable condition at North Manchester General Hospital and a sixth is in London's Northwick Hospital.

Dr Hollyoak said all doctors had been alerted to look out for patients who had recently returned from Hong Hong or southern China and developed sudden fever and flu-like symptoms.

"We only need to be concerned if they become unwell within ten days of having returned," he said. "If they were there six weeks ago they don't need to worry."