A South Korean legislator who has staged a 10-day hunger strike outside China's embassy collapsed on Friday during a rally denouncing Beijing's repatriation of North Korean refugees.

Park Sun-Young, from the conservative opposition Liberty Forward party, fainted while leading the rally by about 100 religious and other activists.

"We want China to immediately stop repatriation," the activists shouted as Park was carried to an ambulance, an AFP photographer at the scene said.

The rally came as visiting Chinese Foreign Minister Yang Jiechi met his South Korean counterpart Kim Sung-Hwan for talks on North Korea and other issues. Yang was scheduled to visit President Lee Myung-Bak later in the day.

Park, 55, launched her fast on February 21, vowing to continue until death unless Beijing ends its policy of sending back North Korean escapees rather than treating them as refugees.

Braving sub-zero night temperatures, she had been living in a tent near the embassy. Her strike has sparked a fresh series of anti-Beijing protests and rallies.

Activists and Seoul lawmakers say about 30 North Koreans who recently fled to China will soon be sent back. They face harsh punishment or even death in their homeland, according to the activists.

Some have already been returned, according to local media reports.

Seoul has repeatedly urged Beijing to treat fugitives from the North as refugees and not to repatriate them. China says they are economic migrants and not refugees deserving protection.

The UN refugee agency and rights watchdog Amnesty International have also urged Beijing not to send the people back. Amnesty says returnees are sent to labour camps where they are subject to torture. (AFP)