South Africa celebrated 16 years of democracy on Tuesday with President Jacob Zuma offering a stark reminder that the effects of unjust apartheid laws lingered.

"Our people still have to daily confront the impact of the law,"  Zuma said in Pretoria, referring to the now-repealed Group Areas Act.

Addressing thousands of people gathered at the Union Buildings for Freedom Day celebrations, he said the Act - which marked the institutionalising of racial partitioning of cities and towns - was still in existence 20 years after it was repealed.

"Many still live in areas once designated for black people... away from economic opportunities and civic services," he said.

"Freedom imposes on us a responsibility to work together in the process of changing such conditions."

This was one example among many which Zuma said needed to be addressed to ensure that people "enjoy[ed] the fruits of freedom".

He cautioned that in four years time - after twenty years of democracy - government would not have sympathy for reasons advanced to explain its failure to make a difference in the lives of the people.

Zuma urged tolerance for other race and culture groupings, saying further engagement was needed to promote common understanding.

This, he said, would stem the tide of criticism exchanged over geographical name changes, struggle songs and the slaughtering of animals to appease ancestors practised in some cultures.

Opposition parties, in their Freedom Day messages, urged South Africans to take a stand against corruption and "empty promises".

Speaking at Constitution Hill, Democratic Alliance leader Helen Zille said South African voters had the power to stand up against corrupt government officials who abuse their positions of power.

"... 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," she said.

Inkatha Freedom Party president Mangosutho Buthelezi, addressing celebrations in Vryheid, KwaZulu Natal, said after 16 years, the message had to go out "that there was something better than empty promises".

"There is something better than a leadership plagued by corruption and scandal.

"There is something better than poor service delivery and constant excuses."

He added that voters would not elect people "whose hands stank with corruption".

The ANC too bemoaned corruption, saying South Africans should defend the gains of freedom by fighting crime and corruption.

"Defending the gains attained through this freedom means fighting crime and corruption, volunteering ourselves to work for good causes in our townships and suburbs," the ruling party said in its Freedom Day message.

The Freedom Front Plus said that democracy was tainted by the high murder rate in the country. FF Plus leader Pieter Mulder said South Africa was racially more divided at the moment than at any other time since 1994.

He said racism was "easy politics" and "difficult politics" was to make a place in the sun for everybody in the country and find win-win solutions.

Congress of the People Parliamentary leader Mvume Dandala said after 16 years there was much to celebrate in South Africa adding, however, that "economic bondage" remained a challenge.

He called on all South Africans to "nurture good relations amongst all" and urged racial tolerance.

The South African Communist Party said the first democratic election in 1994 did not mark an end to the national democratic and class struggle, but brought a struggle on a different terrain.

"We need to place our society onto a different developmental path, one in which meeting social needs is the priority and not profit-driven growth," the party said in a statement.

The country's largest labour federation, the Congress of South African Trade Unions said that a lot more needed to be done before South Africans could say they were truly free.

"We cannot ignore the 58% of South Africans who live in poverty, who cannot really benefit from political freedom as they face a daily struggle to survive," spokesperson Patrick Craven said in a statement.

He said massive inequality had made South Africa the most unequal society in the world.

"Such inequality mocks our struggle to build a free, fair and equitable society. Neither can we celebrate freedom when our society is scarred by such high levels of crime and corruption."