Waka Kotahi Transport Systems Manager for Top of the South Andrew James says contractors have fanned out across the regions to assess damage, clear debris and undertake repairs with the aim of re-opening key sections of SH6 by the end of August.
"We’re pulling out all the stops to restore road access as soon as possible," he said.
“The scale of the damage sustained by highways and local roads here is huge. They can’t be repaired to their previous condition overnight, but we know how crucial these transport links are to communities and businesses in the region."
Waka Kotahi believe SH6 between Havelock and Rai Valley can be re-opened by Tuesday morning, at the Ronga Road/French Pass turn-off.
SH6 between Nelson and Blenheim should also be open by Wednesday morning, James says.
However, there will be speed restrictions and traffic management in place.
"So please factor in longer journey times and delays when planning travel."
He says it will be at least a few weeks before the roads are fully open.
“Although we’ve made considerable progress on State Highway 6 already, there is still a lot more work to do."
He said motorists should expect full lane closures over the coming weeks while repair work is done.
"We will provide more information when further assessments have been carried out and we have more details to share.
"Thank you for your patience and understanding as the mahi continues."
As of Thursday, one-lane traffic is permitted along Rocks Road, SH6, travelling Northbound to Nelson from 8am to 7pm each day.
The length of SH6 from Renwick to Havelock is fully open with temporary speed restrictions.
Waka Kotahi aims to open the length of SH63 from Renwick to Saint Arnaud by the week of September 12, with restrictions.
Heavy vehicles up to 26 tonnes and 8 wheels can now travel single-lane along SH60 from Tākaka to Onekaka, with some temporary closures over the next few weeks while work is done.