The rising tide of elephant and rhino poaching in Africa is spreading to the sparsely-populated vastness of Namibia in the southeast of the continent, latest official figures show.

Between 2005 and 2011 just two elephant were killed, while 121 have been killed in the past two and a half years, according to figures presented by the environment ministry.

And while no rhino were poached between 2005 and 2010, a total of 11 have been killed since then -- rising from one in 2011 to four already this year.

Deputy Environment Minister Pohamba Shifeta told AFP that the government is worried by the trend and is working with law enforcement agencies to tackle the problem.

"We don't want the numbers to escalate further," Shifeta said.

"There is a high probability that attention will shift to Namibia as we have recently experienced."

Across the border in South Africa, rhino poaching has reached crisis levels, with more than 290 killed already this year.

Most of the poaching in Namibia has taken place in protected areas, such as the Bwabwata National Park in the northeast, where 13 elephant were killed in 2012, the environment ministry report said.

"The immediate requirement is to control the emerging commercial ivory poaching in the northeast part of the country and to prevent the westwards spread of rhino and elephant poaching into the Etosha National Park and beyond," Shifeta told a meeting of police officers and rangers.

Namibia has 79 conservation areas covering more than 100,000 square kilometres and inhabited by some 300,000 people.

Several poachers have been arrested in recent years, with the latest suspects being two Asian men who were held in March this year allegedly in possession of rhino horn worth around $230,000 (167,000 euros).

Asia is a major market for rhino horn, where it is believed to have medicinal value, and for elephant ivory.