A drunk driver who killed a 69-year-old woman picnicking with a friend by a Kapiti Coast roadside has been jailed for 4-1/2 years.

Kyle Richard James, 37, a sales assistant of Upper Hutt, was sentenced in the High Court at Palmerston North after earlier admitting the manslaughter of Shelagh Cotter, 69, and causing injury to her friend Marilyn Jeffrey.

He was found to have a breath alcohol level of 949 micrograms after the crash. The legal limit is 400mcg.

The two women were drinking tea on a grass verge near Otaki about 11.40am on October 30 when they were struck by James' Subaru stationwagon.