Large slips came down on two key streets in the Wellington suburb of Karori after a weekend of wet weather.
Birdwood Street in the suburb of Karori was covered in debris early on Monday morning and cars had been unable to get past.
A second arterial route in and out of the suburb, Chaytor Street, was down to one lane, with stop/go traffic control as workers started clearing the slip.
Motorists were urged to use Old Karori Road/Whitehead Road and Curtis Street to go in and out of Karori.
Wellington City Council spokesperson Richard MacLean said Chaytor Street should be clear by the afternoon rush hour, but Birdwood Street, where the slip was blocking both lanes and the footpath, would take several days to be reopened.
The slips were among about 20 reported around Wellington City over the weekend and all others had been cleared, the council said.
Wellington Electricity spokesperson said one property on Chaytor Street was without power and streetlights were out.
Drivers were asked to take care and keep speeds down to avoid running into any new slips.
Heavy rain in the capital in August caused the same two streets in Karori as well as other suburbs, less than a fortnight after a slip threatened properties in Karori and the central city. Wellington had had its wettest July on record this year.