A suspicious device found at a Tawa service station that sparked a callout by the Defence Force bomb squad could be the result of someone tampering with a fuel storage tank.
Roads were closed, fire crews put on standby and trains were stopped for more than four hours on Saturday night while the explosive ordnance disposal squadron was called to the BP Connect service station on the corner of Main Rd and Tawa St.
Service station staff had been doing routine inspections when they noticed an "irregular fitting" on the fuel tank fill point, BP spokesman Jonty Mills said.
Mr Mills was at the scene and said staff alerted police after becoming concerned just before 10pm when they discovered the fitting, which had several wires attached, although the apparatus was later found to be non-electronic.
"It certainly did not look like a normal fitting," Mr Mills said.
CCTV footage was being reviewed and BP has begun an internal investigation into suspected tampering but has ruled out contractors and maintenance workers as the culprits.
"It's worrying for us because we don't know what it is.
"Someone's tampered with it but right now we don't have an explanation," Mr Mills said.
The mystery fitting was later ruled non-explosive by the bomb squad who had dismantled the device by 1.50am.
The cordon around the petrol station was lifted about 2.30am.
Traffic was closed to parts of Tawa St, Main Rd and The Drive, and Tranz Metro stopped all trains between Takapu Rd and Porirua because tracks run through the area. Tawa College principal Murray Lucas made the school's hall available for a neighbourhood evacuation.
Mr Mills said the threat to staff and residents justified the high-level emergency response.
- The Dominion Post