South Africans should never again be denied the right to vote, the Freedom Front Plus said in the Constitutional Court on Wednesday.

Former president Nelson Mandela said this should "never, never again" happen, the party's counsel Barto du Plessis told the court.

"In the context of disenfranchising people, this court should never allow disenfranchisement," said Du Plessis.

The court was taking submissions from eight separate parties on the Electoral Act's provisions that limit which South Africans can vote when overseas.

The Act allowed the overseas vote to government officials, sporting teams competing internationally, and people on business trips or holidays.

However, they had to notify the Independent Electoral Commission within 15 days of the proclamation of the election date of their intention to vote.

Willem Richter, a school teacher working in the UK until the end of the year, had successfully argued in the Pretoria High Court that it was unconstitutional to deny him the right to vote while he was out of the country.

The Constitutional Court must either confirm the high court's ruling or reject it.

The judges spent the morning grappling with why the applications were made so late, with elections on April 22, only six weeks away.

They were given various reasons -- that the people are not as in tune with electoral messages while out of the country, or that there were delays in registering the party making the application.

The A-Party argued that the right to vote was also attached to the right to register, so the court must consider that too.

The Democratic Alliance added another facet by saying it was not enough to only allow people to vote for national representatives, which the act only allows, but that people overseas should also be allowed to vote for provincial representatives.

Civil rights group Afriforum said more countries allow their citizens to vote while out of the country, than those who do not.

Their lobby group's counsel Herman Higgins said the court must also consider the possible perception of undermining the legitimacy of a government by limiting who could vote.

The act also violated constitutional principles of equality by allowing only certain categories of South Africans overseas to vote.

The judges had in turn said they were worried about upsetting the separation of power between Parliament and the judiciary by changing or abolishing laws.