An explosion at a North Shore substation has cut power to more than 2000 homes and businesses.

Multiple traffic lights are also out along Onewa Rd after the explosion also sparked a fire in a power pole on the corner of Onewa and Lake Rds.

Fire Service northern shift manager Jaron Phillips said crews were investigating an explosion at the Northcote substation on Lake Rd.

Motorists were asked to follow give-way rules and take extra care.