"South Africa has lost another 24 rhino since last week," CEO David Mabunda said in a statement.
"The Kruger National Park remains the hardest hit, with 15 rhino being poached for their horn since 20 February 2013."
According to the latest statistics by SANParks the Kruger National Park has had 107 poachings since the beginning of the year.
The national park lost 425 rhino to poaching last year.
Mabunda said a recommendation was made to Water and Environmental Affairs Minister Edna Molewa that the boundary fence between South Africa and Mozambique be reconstructed.
"Minister Edna Molewa said the reintroduction of the border fence was strictly dependant on an analysis of the rhino poaching situation in the Kruger National Park," said Mabunda.
According to stats by SANParks, in 2012, 668 rhino were poached countrywide, in 2011, 448 and in 2010, 333.
Together with the 146 poached so far this year, it brought the total to 1 595 over the past four years.
In the past weeks two alleged poachers were arrested in the Kruger National Park, and two in Limpopo.
Fifty arrests had been made so far this year.
Forty-seven of them were alleged poachers.
The other three had been charged with illegal trade in rhino horn.
Last year a total of 267 arrests were made.