Three more rhino have been killed in South Africa, indicating rhino poaching went unchecked despite mounting efforts to curb the scourge, authorities said on Wednesday.

Africa's rhinos are already endangered and now they are being killed at a rapidly increasing rate.?[File photo]

The carcasses of three white rhino were found on ranches in Limpopo Province on Monday and Tuesday, bringing to total number of more than 80 killed in SA this year, according to the Hawks, a special anti-crime force.

The rhino were believed to have been shot by poachers, said Hawks spokesman McIntosh Polela.

One rhino's horns were removed, but the horns of the other two were not, said Polela.

"Our suspicion is that the poachers were probably disturbed and ran away without taking the horns," said Polela.

He said investigations were being conducted to determine the exact circumstances around the killing of all three rhino and to catch the people involved.

Last year, a record 448 rhinos were killed in SA, including 19 black rhinos, a critically endangered species of which fewer than 5,000 remain in the wild.

That was 34 percent more than in 2010, when 333 rhinos were killed, and nearly four times the 122 lost in 2009.

Rhinos are just one of the many species being poached, the Deputy Minister of Environmental Affairs Joyce Mabudafhasi said earlier.

Mabudafhasi said although the issue of rhino poaching was a government priority, "it is only a part of the larger problem, as many other animals are being poached, even frogs."

Mabudafhasi said South Africa had suffered an 80-billion-rand (about 10.6-billion-dollar) loss in the 2010-2011 financial year as a direct result of environmental crimes that included the illegal trade in abalone (perlemoen), ivory and rhino horn.