Recreational boaties should be extra careful when returning to the waters of Lake Aviemore, as the recent downpour dislodged large logs and debris from the surrounding hillsides.

Environment Canterbury deputy harbourmaster Gary Manch said after heavy rainfall in the Canterbury high country, the debris has ended up in Lake Aviemore, causing a potentially dangerous situation for any unaware boaties.

"The logs and debris can sit just a few inches underneath the water's surface and would cause considerable damage to any vessel that comes into contact with it," he said.

"Take it easy when you're coming back to the lake. Keep your speed low until you're satisfied there is no risk in the area you're boating."

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