Steenkamp one of 2 500 women killed every year
The institute said data on spousal or partner assaults was difficult to find but anecdotal evidence suggested many women were attacked by people they were in relationships with.
"The tragedy of this crime is that it is one of hundreds of similar incidents that play themselves out across South Africa every year," the institute's Lerato Moloi said.
"Hopefully the massive media spotlight focused on this one incident will direct attention on the broader problem and prompt the policy initiatives necessary to combat it more effectively."
She said the effectiveness of the Domestic Violence Act and laws to limit access to firearms needed to be revisited.
Pistorius was charged with murder after Steenkamp, a model and law graduate, was shot dead at his home in the Silver Woods Country Estate, Pretoria, on Thursday.
The Paralympian appeared in Pretoria Magistrate's Court on Friday for a bail application. The matter was postponed to Tuesday.
Decline in murders
The South African Institute of Race Relations said an average of 2 488 women had been murdered every year over the past six years.
Moloi said such crimes had, however, seen a slight decline over the same period.
In 2007 there were 2 602 women murdered in the country. By 2012 that figure had decreased to 2 286.
"If data for all violent assaults, rapes, and other sexual assaults against women are taken into account, then approximately 200 000 adult women are reported as being attacked in South Africa every year," she said.
"The real figure is in all probability considerably higher, as anecdotal evidence suggests that reporting rates may be significantly lower than the number of incidents taking place every year." – Sapa