The New Zealand transport agency is undertaking measures to check the safety of bridges and highways in the state of Canterbury, as aftershocks following last week’s earthquake continue to affect the region.

The region has been hit by aftershocks measuring 5 on the Richter scale following the 7.1 magnitude quake, which hit the nation causing damage to the state highways.

The agency will open State Highway 74 and the on-ramp on the Chaney’s Road on State Highway 1 in Christchurch, which have both been closed since the quake.

The Lyttleton Tunnel had been closed for about three hours to carry out safety checks and was later re-opened as no major damage was recorded.

Canterbury State Highways operations manager Peter Connors said the agency plans to continue the safety assessments as long as they are required to help re-build the region.