Walkers can experience Tasmania's popular new Three Capes Track for half-price as part of the state government's planned celebrations for the 100th anniversary of national parks.

Between July 15 and September the three-night, four-day walk over 46km along part of southeast Tasmania's Tasman Peninsula will cost A$250 ($261.40) per person, down from the usual A$500, Parks Minister Matthew Groom told parliament on Thursday.

"It's fitting that this experience has taken off the way it has this year as Tasmania celebrates 100 years since our national parks were first reserved," he said.

Entry to the state's national parks will be free for a fortnight from September 24 to coincide with school holidays.