One lane has been opened on State Highway 2 after a slip blocked the road north of Upper Hutt on Tuesday morning, closing the Rimutaka Hill road.
The slip came down on Tuesday morning opposite the Te Marua lakes.
The Transport Agency says it will be examining the roadside following the latest slip. Spokesperson Mark Owen says a smaller slip happened in the same place on Saturday.
He says the agency will look at what caused the slip and what can be done to stabilise the area and prevent any further erosion.
Mr Owen says one resident raised concerns about his house being endangered, but his property is at least 15 metres away from the slip face.