Look for policies which cover 'all risks' or 'accidental damage' and then check the small print for exclusions. If you are a home owner then you can often get this as additional cover on top of your home contents cover. That way you are also insured if it gets nicked from your car while you are in the pub after the trip etc.
Bear in mind that this insurance will not cover general use and abuse damage. So if you drag your camera around unpadded underground and handle it with wet muddy hands until it inevitably dies an early death then don't expect to be able to claim. But if you were unfortunately enough to drop it in a stream while using it, or drop a rock on the bag containing it then that would be accidental damage just like a surface accident (and just as unlikely so a fair claim under these sorts of policies). If you properly pack your camera for transport then it should not suffer any worse than a camera used on the hills. I prefer a flexible waterproof bag (e.g. Aquapaq, or Ortlieb map cases) as these are less likely to leak than a hard case (e.g. Pelicase, Daren drum, Otterbox) which will leak if anything solid gets in the seal. Then put the flexible cased camera into a Daren drum or similar padded with foam for secondary waterproofing and to protect from bangs and possible puncture of the flexible case. This also gives good crush protection. That is better insurance in my opinion than a financial policy alone.
