The Transport Agency says it is on track to have the flood-damaged part of State Highway 6 near Harihari on the West Coast reopened on Tuesday.
Heavy rain and flood waters covered more than 40 metres on the South Island highway on the northern side of the bridge on Wednesday, forcing travellers to make long detours.
Mark Pinner, the agency's senior asset manager for the West Coast, says work began on Saturday to divert the Wanganui River back under a bridge so a detour can be put in place.
About 15,000 cubic metres of gravel have been trucked onto the site to build up the river bank.
"They've been trying to push the north bank into the new river channel to push it back in towards the bridge, where it should be, and from the south side there's cuts in the channel to divert the flow there.
"The aim today is fully control the river and get it back to where it was previously under the bridge. The key to us is getting in behind the bridge abutment so that we can bring that up to connect to the road again."
Mr Pinner says the piles supporting the bridge appear to have withstood pressure from the flood and it will be safe to use, provided that the water level continues to drop.
Glaciers still open
Chairperson Rob Jewell says several road closures due to bad weather earlier in the week have given rise to some confusion as to where tourists can and can't go.
Mr Jewell says while the glaciers can't be approached from Hokitika in the north, the road from Wanaka in the south through the Haast is open.
"We're open for business as usual, there's some great activities and attractions here ... just come and experience it - it's a great place."