Speaking on Tuesday, Naledi Pandor also said that Israel is carrying out a campaign of starvation in Gaza.
South Africa has hauled Israel before the International Court of Justice (ICJ) over its genocide in Gaza, infuriating Israel and drawing US censure.
Pandor said that Israel had defied a January interim ruling by the ICJ that it should take action to prevent acts of genocide in the Gaza Strip.
"The provisional measures have been entirely ignored by Israel," Pandor said at the Carnegie Endowment for International Peace during a visit to Washington.
"We're seeing mass starvation now and famine before our very eyes," she said.
"I think we, as humanity, need to look at ourselves in horror and dismay and to be really worried that we have set an example," she added.
Pandor said that Israel's actions may mean other nations believe that "there's license -- I can do what I want and I will not be stopped."
She said that South Africa's post-apartheid democracy was "merely practicing what is preached to us every day" by the West.
"The ICJ has not been respected. And the day an African disrespects (it) I hope we don't go to that leader and say 'Listen, you're out of bounds -- because you're an African, we expect you to obey,'" she said.
South Africa has called on the UN court in The Hague to order measures for Israel to stop "widespread starvation" triggered by its war in Gaza.
The United Nations has warned that Israel could be using starvation as a weapon in its genocidal war against Gaza by blocking the desperately needed aid into the war-battered strip.
The UN said Tuesday that Israel's severe restrictions on aid into war-ravaged Gaza coupled with its military offensive could amount to using starvation as a "weapon of war," which would be a "war crime."
United Nations human rights chief Volker Turk condemned the rampant hunger and looming famine in Gaza.
He lamented the world’s inaction in the face of what he described as a man-made catastrophe despite the UN’s repeated alerts in the past months.
The warning comes a day after a UN-backed report said malnutrition and food insecurity have probably exceeded famine levels in Gaza’s north, and hunger-linked death rates were likely to do so soon.
A global anti-poverty charity on Monday denounced Israel for intentionally preventing the delivery of humanitarian aid to the Gaza Strip in violation of international humanitarian law.