Windhoek - Namibia wildlife authorities on Friday defended the auction of permits to hunt black rhino, saying the kill was aimed at conserving the endangered species.The auction conducted in the US by The Dallas Safari Club is part of a government approved annual quota, in place since 2012. It gives permission for the killing of five black rhino per year."We have been confronted by individuals and organisations who express their dissatisfaction about the programme...they sometimes think that we do things randomly," said the Deputy Minister of Environment Pohamba Shifeta."People should not be worried, we have a programme and policies that we are following."Shifeta said the auction which ends on Saturday will be followed by a hunt at a national park in the semi-desert southern African country that has a black rhino population of nearly 1 800.Media reported that The Dallas Safari Club expected the auction to generate $250 000-$1 million.Namibia says proceeds from that the hunt which has drawn widespread criticism from wildlife groups go to a conservation fund."We have never experienced a reduction of rhinos, in fact, the number has increased," Shifeta said. Namibia is less hit by rhino poaching compared to South Africa, with only 10 killed since 2006, according to the international wildlife trade monitoring network Traffic.Across the border, rhino poaching has reached crisis levels, with nearly a thousand killed in 2012.Black rhinoceros are internationally considered an endangered species and the World Wildlife Fund says there are less than 5 000 rhino remaining in Africa.The Namibian government also grants licences for the hunting of big game like elephant and lion.