The Mountain Safety Council says rivers are a leading killer of trampers, and people should remember that no-one ever has to make a crossing.
Eight people drowned trying to cross rivers in the four years to 2008.
Chris Tews from the council says people sometimes decide to make a crossing when it isn't necessary.
"It could be that it's a short cut, he says. "It's what we call 'get-home-itis' where the cars are on the other side of the river, or the hut's just on the other side of the river, and they let their guard down ... and they're swept away."
Chris Tews says if people do cross, they must plan where to enter, where to get out, check the bottom of the river, the water flow and plan what will they do if they get into difficulty.