Officials in Newfoundland and Labrador are investigating a computer security breach involving sensitive patient information that may have been accessed through the internet.

The data, including lab test results for infectious diseases such as HIV and hepatitis along with patient names and health numbers, was stored on a government desktop computer, said Health Minister Ross Wiseman.

The computer was unplugged and taken to the home of a consultant working for the Provincial Public Health Laboratory, something Wiseman said should never have happened.

"That was an inappropriate use. Obviously individual computers that are available for work are there for the workplace only," he told CBC News.

On Friday, Attorney General Jerome Kennedy called the security lapse a "very serious matter that required immediate action" to determine whether there has been "any illegal activity or hacking."

On Tuesday night, someone claiming to be a computer security specialist from somewhere outside the province called the consultant and said they were able to access the data.

Kennedy said it's unclear how many people's private medical information may have been exposed.

The government has hired a computer security firm to lead its investigation and has asked its own chief information officer to determine the scope of the breach and how it could have happened.