South Africa's Kruger National Park on Wednesday said four staff members, including a field ranger, have been arrested for rhino poaching, which has killed 43 of its animals so far this year.

The four were arrested after two freshly killed rhino, which had been shot and dehorned, were found in a south-western section of the giant park where the officials were stationed and which has lost 11 animals since January.

"It is a very sad day for South Africa to find out that the unscrupulous and revolting hands of the poaching syndicates have stretched as far as to taint the hands of those trusted with the great responsibility of being guardians of our natural heritage," said national parks chief David Mabunda.

Those arrested included a field ranger, two field guides and a traffic cop who is the second to be arrested for rhino poaching. Another field ranger is at large, park spokesman William Mabasa told AFP.

Rhino poaching has claimed 80 of the giant animals in the first two months of this year alone in South Africa -- against a total of 83 lost in all of 2008.

A record 448 were killed last year, with Kruger bearing the brunt of the bloodbath. The tourist hotspot lost 252 rhinos to poaching despite the deployment of soldiers last April to crack down on the problem.

The animals' distinctive horns are hacked off to be smuggled to the lucrative Asian black market, where the fingernail-like substance is falsely believed to have powerful healing properties.

Officials have arrested 50 people on poaching charges so far this year.