Major plans for Canterbury's roadways as a historic speed-limit change comes into force

From today a section of the Christchurch Southern Motorway will have a speed limit of 110 kilometres an hour - becoming the first of its kind in the South Island.

About 70-percent of public submissions on the change last year supported the move.

South Island Minister James Meager says improvements on Brougham Street, in Rolleston, and on a second Ashburton bridge are in the works.

He says upgrades between Lyttleton Port to Timaru Port are also being explored.