Crews have worked through the night, to repair last night's burst watermain outside Auckland Town Hall

Watercare says the burst has been isolated, about four metres of affected watermain was repaired, and water was restored to affected properties just before 6am.

A one-way detour remains in place while crews finish off repairs and reinstate roading surfaces, affecting some bus services.

Watercare is advising anyone who has discoloured water to flush their taps until they run clear.