Nobel Peace laureate Archbishop Desmond Tutu has strongly condemned a new media law, which South African MPs are set to vote on shortly. He called it \"insulting\" and warned it could be used to outlaw \"whistle-blowing and investigative journalism\". South African journalists wearing black have staged a protest against the so-called \"secrecy bill\" outside the headquarters of the governing ANC. The ANC says the law is needed to safeguard state secrets. The African National Congress has a two-thirds majority in parliament and so the bill is expected to pass, unless the party leadership has a last-minute change of mind. The Protection of State Information Bill proposes tough sentences on anyone possessing classified government documents. The BBC\'s Nomsa Maseko in Johannesburg says the bill has come under closer scrutiny after President Jacob Zuma\'s spokesman Mac Maharaj filed a lawsuit against South Africa\'s Mail and Guardian newspaper - preventing it from publishing information linking him to a controversial arms 1999 deal. The South African media broke the story using secret documents, but under the new law, journalists and their editors would face stiff jail sentences for similar disclosures, she says. Secrecy saves lives On the eve of the vote, Archbishop Tutu appealed to lawmakers not to approve the bill. He said it was \"insulting to all South Africans to be asked to stomach legislation that could be used to outlaw whistle-blowing and investigative journalism... and that makes the state answerable only to the state.\" South African Nobel prize-winning author Nadine Gordimer has also condemned the bill, which she said was taking South Africa back to the years of white minority rule, the Johannesburg-based Times Live news site reports. The bill was was \"totally against\" freedom, she said. \"The corrupt practices and nepotism that they [politicians] allow themselves is exposed if we have freedom of expression,\" Ms Gordimer is quoted as saying. South Africa\'s National Press Club (NPC) - backed by the Right2Know campaign group - has called on people to wear black to show their opposition to the proposed legislation. It has called for protests outside in parliament in Cape Town, as well as Johannesburg. NPC chairman Yusuf Abramjee said the media would no longer be able to publish classified information, even when it was in the public interest. However, the ANC has rejected such criticism, saying the bill meets international standards and secrecy is sometimes needed to save lives. South Africa\'s highly restrictive apartheid-era media laws were overturned when it became a democracy in 1994. Archbishop Tutu won a Nobel Peace Prize for his opposition to white minority rule but has recently become a vocal critic of the ANC government.