South African voters have the power to stand up against corrupt government officials who abuse their positions of power, opposition Democratic Alliance (DA) leader Helen Zille said on Tuesday.

"When people in South Africa today see all the corruption and power abuse and lack of delivery, they get angry and feel powerless," Zille said during her Freedom Day speech at the Constitutional Court.

"When this happens, we must remember 27 April 1994, and remember that we are not powerless.

"We have the vote," she said.

"If we don't use our vote to change the people in power, there will be more and more abuse, and more and more corruption, and we will become a criminal State."

Zille criticised the African National Congress (ANC) and President Jacob Zuma, saying that they were not made accountable for their actions.

"He [Zuma] has undermined the Constitution to make sure he does not have to go to court and answer to over 700 counts of corruption against him," Zille said.

"He abuses power to protect his friends, like Shabir Shaik, from the law, while persecuting his political opponents.

"He supports a system in which the ANC uses the people's money to make themselves rich, that is what is happening at Eskom.

"When you pay your increased electricity tariffs, it will be a reminder of what the ANC's corruption is costing you."

Using the demise of democracy in Zimbabwe as an example, Zille urged South Africans to use their vote to "get rid of a government that undermines the Constitution."

"Let us remember this lesson on this Freedom Day, in a democracy, people get the government they deserve. We certainly deserve better than the ANC," Zille said.