A man stands a next to an attempted copy of the offending art work by an unidentified artist.

A man stands next to a spoof of the painting depicting Jacob Zuma. Photo: AP

A lawyer for South African President Jacob Zuma has broken down in tears as he tried to convince three judges that the display of a portrait that depicts Mr Zuma's genitals is unlawful.

The three South Gauteng High Court judges called a recess after the emotional display. After a break of more than two hours, judges and lawyers agreed to resume at a date to be decided later.

Mr Zuma is asking the High Court to issue an order that display of the now-defaced painting The Spear, by Brett Murray, violates his constitutional right to dignity. The gallery and the artist counter that freedom of expression, also protected by the constitution, is at stake.

Two men walked into the Goodman Gallery on Tuesday and defaced the portrait with paint, saying later they were acting to defend Mr Zuma.

The gallery then removed the painting and closed indefinitely.

The court hearing was broadcast live on television. Leaders of the ruling African National Congress were present, as were several of the 70-year-old Mr Zuma's children. Outside the courthouse, hundreds of Zuma supporters danced and sang.

The lawyer, Gcina Malindi, argued that the court should take into account not just the opinions of a ''super class'' of art experts, but how the painting was likely to be seen by the country's black majority, denied education under apartheid.

Mr Malindi said many blacks still lived in poverty after the end of apartheid in 1994. He then sobbed. His colleagues rushed to put their arms around his shoulders.

ANC spokesman Jackson Mthembu described Mr Malindi as a leading member of the ANC who had been tortured for his anti-apartheid activities.

''That's why this is emotional,'' Mr Mthembu said.