"The project is a complex one on a busy road and we are making steady progress with the first 16m road bridge open and the 36m long, 34 tonne pedestrian bridge in use," Mr Johansson says.
Between July and September 120,000 cubic metres or over 4000 truck and trailer loads of fill was left to settle on the Welcome Bay side of the site.
The second bridge was expected to be completed mid next year.
Members of the public can attend the open day any time between 10am and 3pm on Saturday .
The guided walks will take place every hour from 10am. The walk is about 2km long and will take about an hour. There will be a free shuttle back to the school.
To view the digital animation of the project and sign up for regular updates go to: www.nzta.govt.nz/hairinilink