The "essential" maintenance work was due to begin today and cause traffic restrictions for the next three weeks.
Mr I'Anson said these restrictions were necessary to ensure the work was done as quickly as possible.
"While we acknowledge that it may be frustrating for people, the traffic plan will mean the Saddle Rd maintenance work will be completed sooner than it otherwise would be, if the work was done under a Stop/Go programme,
"The work will also ensure that people can continue to access Woodville and businesses there, while the gorge is closed."
Mr I'Anson said it was "too early to tell" when the Manawatu Gorge might reopen in light of recent events.
Slips were "hampering" efforts to reopen the road and only when the movement slowed or stopped could the situation be reassessed, he said.
Saddle Rd restrictions will affect traffic between the hours of 9am and 3pm; traffic moving from Ashhurst to Woodville would move through a single traffic lane on Saddle Rd and traffic going from Woodville to Ashhurst would travel via a detour over the Pahiatua Track.
Roadworks and restriction updates will be displayed around the routes and NZTA contractors will be putting up extra signs around Woodville about the detours.