The grandson of late South African president and anti-apartheid activist Nelson Mandela arrived in Johannesburg on Wednesday after being detained and then deported by Israel, which prevented the flotilla he was part of delivering aid to Gaza.

Mandla Mandela, who returned home with four other South Africans, said he and the group he was with were held in an Israeli prison for six days before being released via Jordan.

"We were handcuffed with cable ties tied tightly behind our backs, taken off our boats, put on the platform and paraded for all ... to see," Mandela, 51, said at the airport, where he was greeted by supporters waving Palestinian flags.

"But it's nothing compared to what Palestinians have been subjected to on a daily basis," he said, referring to Israel's military offensive against Hamas since the Palestinian militant group's deadly attack on Israel two years ago.

Israel says reports of hunger in Gaza are exaggerated and dismissed the flotilla as a publicity stunt benefiting Hamas. It has denied mistreating the hundreds of people it detained, who included Swedish activist Greta Thunberg.