Some businesses in Canterbury shut their doors again on Wednesday, after the magnitude 5.1 aftershock.
It was extremely shallow, at a depth of 5km and was centred close to Lyttelton.
The Lyttelton tunnel was closed while engineers inspected cracks, but it has since reopened.
The port is still running, but the port company says some employees were unable to get to work because of the tunnel's closure.
The Palms shopping centre in the suburb of Shirley closed following the aftershock, as have two Countdown supermarkets.
Nine Countdown supermarkets had minor stock damage and are still open. However, the Colombo St and Ferrymead Countdowns are shut.