A large volume of traffic leaves at Gillies Ave to head for Auckland International Airport.

The motorway then crosses the narrow Newmarket Viaduct, before turning to follow the North Auckland Rail Line to Ellerslie.

Immediately after the Mt Wellington Highway interchange, the motorway curves south to head towards the Tāmaki River.

After crossing the Tāmaki River, the motorway forms a boundary between the suburbs of Papatoetoe to the west and Ōtara to the east.

The motorway then curves towards the south-westerly direction where it crosses Great South Road at the Takanini interchange.

In 1969, the motorway was extended to Wellesley Street, allow traffic in both directions to access the central city.

The extension bypassed the traffic light-controlled crossroads at St Stephens, known to be an accident blackspot and causing delays of up to two hours during holiday periods.

Accompanying the extension was the building of the first part of the Waikato Expressway, which allowed traffic from the Southern Motorway to have a clear run as far as the State Highway 2 interchange on the south side of the Bombay Hills.