Bearing the message that their livelihoods were in peril, hundreds of women farmers tried Friday to gatecrash UN climate talks in Durban, where they were peacefully held back by police.

The women, from 10 countries across southern Africa, converged on the conference to testify how storms and heatwaves, intensified by climate change, were wreaking havoc on an already meagre sustenance.

Many wore green-on-black T-shirts reading "Rural Women Assembly" and carried hand-scrawled banners, including one that said: "Women Are the Guardians of Seed, Life and Earth."

About 50 police in full riot gear prevented the women and other protesters from entering the venue.

There were no arrests or injuries, and the atmosphere was more festive than feisty. But the women -- from Angola to Zimbabwe -- had a serious appeal to make.

"We are getting a lot of difficulty and suffering with water," said 75-year-old Betty Nagodi, from an arid region of northern South Africa.

"Now we don't know when it will rain. And then when it does, the hail knocks down all the tomatoes, butternut and other things," she said, fanning herself under the shade of a towering acacia.

Rising temperatures and shifting rainfall patterns could adversely affect water flows on the Limpopo river system, leading to production shortfalls and conflict over water use, according to a report earlier this month by the Consultative Group on International Agricultural Research (CGIAR).

"We have seen how climate change has disrupted the seasons, completely changing agricultural production cycles. It affects our lives very directly," said Fatima Shabodien, an activist from Cape Town, South Africa, also taking part in the rally.

"We are here to call attention to the impact of climate change on the livelihoods of rural women."

For Lilian Kujekeko of Zimbabwe, the diplomats and politicians negotiating behind closed doors -- "most of them men" -- needed to know that global warming was not an abstraction, and that in Africa it was women who were bearing the brunt.

"We are the ones who suffer most of the consequences of climate change. We look after families. So why are we not there in the conference?" she asked emphatically.

Weather in her home region has become increasingly erratic in recent decades, she said, with one recent heatwave peak topping 45 degrees Celsius (113 degrees Fahrenheit).

The region's staple crop, maize (corn), is "very sensitive" to fluctuations in rainfall, she noted.

A report on climate change and extreme weather earlier this month by the UN's Intergovernmental Panel on Climate Change (IPCC) predicts more droughts for large swathes of Africa, raising the spectre of famine in regions where daily life is already a hand-to-mouth experience for millions.

Factor in the biggest population boom of any continent over the next half-century and the danger of food "insecurity" in Africa becomes even greater, it cautions.

Some 15,000 diplomats, experts and campaigners at the talks under the 194-nation UN Framework Convention on Climate Change (UNFCCC) are trying to breathe life into international negotiations tasked with fighting the threat of climate change.

Non-governmental organisations (NGOs) and local grassroots groups have announced a protest march under the banner of "climate justice" for Saturday, and said they expect a turnout of up to 20,000.

The 12-day talks enter a high-level phase next week with the arrival of ministers, ending on December 9.