The final phase of work on the nearly century-old bridge includes replacing 14 damaged bracing beams under its cycle path.
NZTA said stop/go traffic management and a temporary speed limit of 30km/h would be in place with delays up to 30 minutes expected.
Transport Rebuild East Coast crews have so far repaired concrete piles on seven piers in the river, which NZTA said has not been visible to motorists.
As part of the new work, a temporary scaffold will be constructed on the bridge to enable safe use by cyclists and pedestrians, with signage in place.
The work depends on fine weather and could be postponed at short notice, NZTA said.
The agency hopes disruption will be minimised by restricting work to off-peak times.
According to the latest available statistics, the bridge carries an average of 14,618 vehicles a day, with heavy vehicles comprising about 3%.
In August 2009, replacement of the bridge was flagged in NZTA announcements, saying an investigation was included in a $214 million investment in land transport in Hawke’s Bay.
It suggested a possible start in the 2011-2012 year.
However, the John Key Government introduced the Roads of National Significance (RoNS) programme excluding any work in Hawke’s Bay, and it was announced in 2012 that the Waitangi Bridge replacement would not take place.
Rebuilt from 1931 Hawke’s Bay earthquake times and repaired after 1938 floods, it was decided to “overhaul” the bridge and extend its life by 15 years.
In Cyclone Gabrielle, on February 14, 2023, road links between Napier and Hastings were cut, with the Waitangi and Expressway bridges impassable and Waiohiki (Redclyffe) and Brookfields bridges collapsed.
Waitangi Bridge was the first reopened, with a path cleared after the river flooded the structure and the approaches.
Doug Laing is a senior reporter based in Napier, with almost 39 years’ continuous experience in the region, with the Daily Telegraph in Napier and with Hawke’s Bay Today, covering most aspects of local and regional news.