By Alastair Leithead BBC correspondent in Cape Town

Thousands of demonstrators campaigning for HIV/Aids treatment in South Africa have been holding a protest outside parliament in Cape Town, coinciding with the annual State of the Nation speech by President Thabo Mbeki.

The head of the Treatment Action Campaign, Zaki Akmad, warned the government it could face civil disobedience.

Our president didn't deign to speak about treatment of people living with HIV Zaki Akmad Aids activist

Amid the pomp and ceremony surrounding the opening of the South African parliament, Mr Mbeki discussed a variety of issues, including Iraq.

He also touched briefly on Zimbabwe, but on the issue of health again played down the significance of HIV/Aids, blaming deaths on tuberculosis ahead of the virus.

TB is the secondary infection many Aids sufferers die from, but something President Mbeki is shy to connect to the HIV virus.

The country will make a "comprehensive response" to the health problems facing South Africa, President Mbeki said.

"We will further intensify the efforts to reduce the incidence of the leading killer disease, TB," he said, referring to Aids only later in the address.

Civil disobedience

As he finished his speech, the Treatment Action Campaign march and rally began in Cape Town.

The TAC has forced the government to change its policies on AIDS treatment through the courts, but is now fighting for anti-retroviral treatment for all infected.

Activists are threatening civil disobedience

"We are seriously worried that our president didn't deign to speak about treatment of people living with HIV," said Mr Akmad.

"We hope that he will wake up and read the signs."

He added: "But if our government does not listen to us, then we will embark on a campaign of civil disobedience.

"As in the old days, a campaign of peaceful, civil disobedience to ensure that we have a national treatment and prevention plan, to ensure that people living with HIV receive treatment."

It was one of the biggest marches Cape Town has seen in the last few years.

And in a country like South Africa, where one in nine people are HIV positive, it is an issue that is not going to go away.