Lyttelton Tunnel - single lane overnight
Maintenance works will disrupt traffic flows through Lyttelton Tunnel tonight.
The NZ Transport Agency (NZTA) said normal traffic would be restricted to a single lane between 8pm to 6am.
Trucks carrying dangerous goods, requiring tunnel closures, would also be affected.
They would only be allowed to pass through the tunnel between 7pm and 8pm, 12.30am and 1am and 6am and 7am, NZTA said.
''NZTA apologises for the inconvenience caused to road users, however these works are for essential maintenance and need to be undertaken in this timeframe.''
Meanwhile, Christchurch can expect high cloud, possible morning drizzle and strengthening north-easterlies today.
MetService is forecasting a high of 13 degrees Celsius.