South Africa's arts and culture department says it had no idea two sculptors had secreted a rabbit in nine-metre bronze statue

A new, nine-metre sculpture of Nelson Mandela is billed as the biggest statue of the South African leader. It also has a tiny, barely visible quirk: a sculpted rabbit tucked inside one of the bronze ears.

South African officials want the miniature bunny removed from the statue, which was unveiled outside the government complex in Pretoria, the capital, on 16 December, a day after Mandela's funeral. The department of arts and culture said it did not know the two sculptors, Andre Prinsloo and Ruhan Janse van Vuuren, had added a rabbit, said to be a discreet signature on their work.

The bronze rabbit, sitting on its haunches with one floppy ear, is about half the height of the ear canal.

"It doesn't belong there," said Mogomotsi Mogodiri, a department spokesman. "The statue represents what everyone in South Africa is proud of."

His department said in a statement that there are discussions on "how best to retain the integrity of the sculpture without causing any damage or disfigurement".

Translation: pull the rabbit out of the ear without botching the statue.

The giant work stands with arms outstretched, symbolising Mandela's devotion to inclusiveness, outside the Union Buildings, where the body of the prisoner who opposed white rule and became South Africa's first black president lay in state after his death at the age of 95 on 5 December.

Earlier this week, the South African newspaper Beeld quoted the artists as saying they added the rabbit as a trademark after officials would not allow them to engrave their signatures on the statue's trousers. They also said the rabbit represented the pressure of finishing the sculpture on time because "haas" – the word for rabbit in the Dutch-based Afrikaans language – also means "haste."

Paul Mashatile, the arts and culture minister, said the sculptors had apologised for any offence to those who felt the rabbit was disrespectful toward the legacy of Mandela.

The government had appointed Koketso Growth, a heritage development company, to manage the statue project. Its CEO, Dali Tambo, son of anti-apartheid figure Oliver Tambo, said he was furious when he heard about the rabbit, and said it must go.

"That statue isn't just a statue of a man, it's the statue of a struggle, and one of the most noble in human history," Tambo said. "So it's belittling, in my opinion, if you then take it in a jocular way and start adding rabbits in the ear."

He said it would be like depicting Barack Obama with a mouse in his nose.

Tambo said the artists, who belong to South Africa's white Afrikaner minority, were selected for their talent but also in part because the project was a multiracial effort in keeping with Mandela's principle of reconciliation. He said their signatures could be added on the statue in a discreet place, perhaps on Mandela's heel.