Norfolk is part of trials of the government's new test, track and trace system, the county council's director of public health said.
The scheme, which has been labelled a key component in the fight against coronavirus, is being rolled out in 11 counties across England from today.
Dr Louise Smith, director of health at Norfolk County Council, told BBC Breakfast that the pilot scheme "starts now".
She said they were working closely with the NHS to identify cases early and then test those who have been in contact with those confirmed patients.
Dr Smith said people who have been diagnosed would be asked to log details online of where they have been and who they had been in contact with from two days before they became unwell and up to seven days afterwards.
"When we've got those details, we would then contact people either through the website or from the call centres, get in touch with those people who have been in contact and arrange for them to have a test," she said.