Spokesman Simeon Brown says National would return many state highways to 100kph from 80 and local roads to 50 from 30.
He says the party would also design new highways where motorists could travel at 110.
"National will repeal and replace the rules that set speed limits so that economic impacts - including travel times - and the views of road users and local communities count, alongside safety," he said.
"It makes no sense to have roads that can safely accommodate higher speed limits, only to require motorists to drive more slowly."
He said National would also reduce the use of road cones and limit temporary speed restructions.
"Temporary traffic management keeps roadside workers and motorists safe during construction or maintenance activities," he said.
"However, excessive use of road cones and speed limit reductions - sometimes left in force when work is complete - simply slow traffic and frustrate drivers, without improving safety."
Brown said the current limits were slowing down people from going about their daily lives, under the guise of safety.
