The tunnel - part of a 5km, six-lane motorway link from the Great North Rd interchange at Waterview to Maioro St in Mt Roskill - is a key part of the long-awaited Western Ring Route.
NZTA Auckland highways manager Brett Gliddon said the tunnel's completion was a significant milestone for the $1.4 billion project.
"This is a fantastic achievement."
Mr Gliddon said the breakthrough was completed safely and ahead of schedule.
"It is a huge engineering feat for New Zealand, one that is attracting worldwide attention."
Alice will now be turned around to bore the northbound tunnel. However, turning around the 90m-long, 3100 tonne machine and reconnecting its cutting head and three trailing gantries was not expected to be completed until early next year, when tunnelling on the second tunnel could commence.
The machine's second run, from Waterview to Owairaka, was expected to be completed in about October next year.
About a year of work would then be needed to complete the mechanical and electrical fit-out of the tunnels, including completing ventilation buildings at both ends and constructing 16 cross-passages to connect the tunnels.
The entire project - which also involves building surface connections to the existing motorways, 9km of new cycleways, new community amenities such as walkways, playgrounds and skateparks, and planting some 150,000 trees and shrubs - was due to be completed in early 2017.
The Waterview Connection was one of five projects to complete the Western Ring Route as an alternative to State Highway 1 through central Auckland and across the Auckland Harbour Bridge.
It has been prioritised by the Government as one of its roads of national significance.
