The Department of Conservation says trampers are putting themselves in danger by not consulting with experts about dangers on walks in national parks.
Earlier this year, Indonesian student Yessica Asmin, 22, was swept away while crossing a swollen river on the Milford Track, after the guided summer walking season finished.
One of the trampers who was with Ms Asmin when she died - German backpacker Sebastian Keilholz criticised DoC, saying the warnings weren't good enough.
DoC southern region services director Allan Munn told Nine to Noon a review of the off-season information system found it was fundamentally sound.
And he said people need to talk to hut wardens when on tracks to know what the risks are.