Signage outside the township of Te Anau warns drivers of the avalanche
The weekend avalanche left trees and snow up to five metres deep blocking several sections of State Highway 94 between the Hollyford turnoff and the Te Anau side of the Homer Tunnel.
Two other sections were blocked on the Milford Sound side of the tunnel.
The road had been due to reopen on Thursday.
New Zealand Transport Agency Southland area manager Peter Robinson said explosives would be used to dislodge unstable snow from the most at-risk areas.
The likely cause of the avalanches was the combination of snow, rain and last month's 7.8-magnitude quake, which had made the snow unstable, he told The Southland Times.
