Nobel peace laureate Archbishop Desmond Tutu on Thursday added his voice to calls for a judicial inquiry into the multi-billion rand arms deal.

In the prepared text of his speech for the Dullah Omar memorial lecture at the University of the Western Cape, he said South Africans could not pretend corruption was no longer a serious problem.

"We need to do something about the arms deal," he said. "We owe it to those who paid a heavy price for our freedom, we owe it to ourselves, we owe it to our future that a thorough independent judicial inquiry happens as a matter of urgency. "It is not going to go away."

He said the church had warned that South Africa's enemies were not military, but poverty, disease and homelessness. "To buy sophisticated machines we did not need, for which we did not have the trained personnel, would be laughable if it was not so serious."

Tutu's call for an inquiry into the deal echoes those made recently by opposition parties, and follows the tabling of a fresh set of parliamentary questions to President Thabo Mbeki about his role in it.

German prosecutors, who are probing the German consortium that supplied frigates as part of the deal, reportedly allege bribes were paid to both South African officials and members of cabinet.

African National Congress president Jacob Zuma is due to go on trial in August on a charge of corruption related to the deal.

Tutu also used the lecture to tackle a range of other issues. He said South Africa's free press had proved a vigilant watchdog and an important institution of civil society.

"Sadly we cannot say the same about our public broadcaster which has far too frequently been sycophantic and reminiscent of the SABC of old, so much an echo of His Master's Voice," he said.

He said proportional representation had had its place in South Africa's transition to democracy, but the time had surely come to scrap party lists.

"We should now have constituencies electing their representatives directly. "The party list basically turned parliamentarians into voting cattle."

People should also be able to vote directly for the president, which would spare the country the tensions of two centres of power.

He also criticised South Africans' lack of respect for laws, including traffic laws.

"We are all guilty but I think our taxis take the cake, they speed, they open a new lane where none should exist, they swing into moving traffic because they jump the queue."