Spokesperson Captain Mohlaka Mashiane said seven women and three men died when the bus overturned on the N1 North.
"We can confirm that all the deceased were Zimbabweans. The driver lost control of the bus and it overturned and it killed ten people instantly. We found people scattered all over. Thirty were taken to hospital."
He said the bus was travelling from Zimbabwe to Gauteng when the accident happened just before 03:00.It was unclear what caused the driver to lose control of the vehicle. "The road itself was clear and there were no barrier lines."
Police have not yet been able to identify whether the driver is amongst the dead or injured.A case of culpable homicide has been opened.
More Zimbabweans are flocking into South Africa daily following visa relations by South Africa which require that Zimbabweans stay in the country for 90 days.
Many Zimbabweans have been searching for jobs in South Africa after a decade of economic collapse and political instability in Zimbabwe. Although, a new government of unity is in place only about 10 percent of industry is operating.
Zimbabwe requires USD 8,5 billion to restore the economy.
Prime Minister Morgan Tsvangirai is currently on a tour of Europe and America to drum up financial support for the broke government. He was in Netherlands at the weekend and he is also expected to visit Britain, France, Sweden and Brussels as well as meet US President Barack Obama during a four-day trip to Washington.
The Dutch promised 14.7m euros (USd 20.5m) in aid to Zimbabwe, mainly for humanitarian efforts and said it would give more if Zimbabwe returns to rule of law, stop human rights abuses and open up the media.