New Zealand Transport Agency Waka Kotahi said work to repair the side panels on the Rangitata river bridge will start on Thursday, July 31, and continue until Tuesday, August 5.
There will be temporary traffic lights and a 30km/h speed limit from 8am to 5pm while the work is carried out.
"Motorists can expect delays of up to 15 minutes and should plan their journeys accordingly," NZTA said.
Then from Tuesday, August 5, until Thursday, August 28, road users should expect delays between Cheviot and Spotswood as trees are removed along SH1.
Stop/go traffic management and a 30km/h speed limit will be in place on weekdays between 6am and 6pm so the tree removal work can be safely carried out.
"These are downed trees from a wind event earlier this month," NZTA said.
"Once again, motorists can expect delays of up to 15 minutes and should plan their journeys accordingly."
