The Transport Agency expects to reopen State Highway 3 through the Manawatu Gorge in one direction by 4pm tomorrow.
Palmerston North state highways manager David McGonigal said westbound motorists would be able to use a newly-built temporary road but drivers going the other way would still have to use a diversion via the Saddle Rd.
Officials would decide on Friday whether to open the road in both directions. If they do the road will be open to westbound traffic from 7am to 7pm and eastbound vehicles the rest of the 24-hour period.
Mr McGonigal said the road would be monitored around the clock to ensure it operated safely. Conditions in the gorge were likely to change at short notice in the event of bad weather and motorists would need to keep a close eye on electronic roadside signs.
The road was closed on August 18 last year because of a slip. It reopened for three days before another, massive slip closed it again.
