Authorities are urging Halloween travellers to avoid the Basin Reserve and Mount Victoria Tunnel as fans gather for the Robbie Williams concert this evening.
Simon Perry, Wellington City Council events operations manager, said cars should avoid the Basin area and Mt Victoria tunnel all day.
From 6pm, the road surrounding the Basin Reserve will be down to one lane until 11pm.
"To reduce the pressure on this area, people should use the quays, Oriental Bay and Evans Bay roads to move to and from the eastern suburbs and the airport," Mr Perry said.
"Also use Taranaki Street to access the urban motorway, southern suburbs, and Wellington Hospital."