Transporting New Zealand reported some freight operators would not have been able to pass on the extra costs caused by the detour.
The reopening meant the demand on labour would ease because of the reduced travel time, the association said.
“As well as improved productivity, the reopening is good news for supply chain resilience.”
NZTA maintenance and operations regional manager Roger Brady said invasive construction methods could be used because the road was closed.
The methods would not have been possible under stop/go traffic management, he said.
“It means SH1 is being brought up to a higher standard quickly, and New Zealanders can get back on a quality road surface sooner.”
Transporting New Zealand chief executive Dom Kalasih said the association had supported a temporary road closure to allow work to be completed faster.
Before the works, NZTA said the stretch of the road was one of worst in Waikato, and among the most challenging to fix.
The road works were part of the country’s “largest and most ambitious” maintenance project, the Tīrau to Waiōuru maintenance programme.
Ruapehu businesses along the detour route experienced a boost. Traffic was diverted to small towns like Ohakune, National Park, Taumarunui and Raetihi.
Before the closure on January 13, weekday traffic on SH4 averaged 2647 vehicles, according to NZTA.
During the first week of the detour, this jumped to 7149 vehicles and increased further to 7730 in the second week.
Less than two weeks into the closure Helen Brown from Utopia Cafe in Ohakune said the closure had been “freaking amazing” for business.
Traffic management and speed restrictions will be in place in some parts for the first three to four days after the reopening.
Further work to finish the road surfacing will happen later in the year, and mostly be carried out at night.