Michael Quinn, the chief electoral officer for Elections New Brunswick, said two laptop computers were taken from its office in downtown Fredericton some time after business hours on Friday.
One of the laptops contained a voters list that includes information such as driver licence numbers, birthdates and phone numbers of the 553,000 eligible voters in the province. But Quinn said the computer contains security features such as password protection and data encryption.
"Although it contained sensitive data ... it is not something which is easily accessible," he told a news conference.
The other computer was being used for software upgrades, he said.
Quinn said he doesn't believe Elections New Brunswick was targeted in the break-in because the office where the laptops were stolen is not marked.
Fredericton police Cpl. Rick Mooney said video surveillance shows a male suspect.
"Detectives are currently working on it to determine more about the identity," Mooney said.
New Brunswick's privacy commissioner said the incident has her concerned.
"Is it foolproof or hacker-proof? I don't think so," Anne Bertrand said. "But I am reassured that there was a good amount of protection of the data on those laptops."
The theft comes weeks after a staffer with Elections New Brunswick inadvertently released the same information to legislative members and political parties. At the time, Quinn said the privacy breach was due to "human error," though last week he said all of the discs containing the information had been retrieved and recipients have signed declarations that no copies were made.
Quinn said locks for the computers have since been purchased — a measure that should be implemented for any computer with sensitive information, Bertrand said.
Fredericton police are also investigating a theft of a computer from Invest NB, a government agency, in the same block as Elections New Brunswick's office.
Invest NB vice-president Louis-Philippe Gautier said the theft was discovered Monday morning, but the computer contains no sensitive data. He said any data is saved on the agency's network.
Bertrand said she expects to conduct an investigation into both thefts.