Dong Jiqin is watching a provincial television channel instead of the Beijing Olympics this summer because the arrest of his dissident wife has taken the gloss of the celebrations.

"I cannot watch the Games," Dong said from his cluttered cement-floor living room-dining room combo in the heart of the capital. "I'm afraid my wife isn't safe. We think the Olympics should be held, but I am just not in the mood to watch it."

The government has defended the stepping up of security, with more than 100,000 police and troops on patrol in Beijing, citing terror threats to the Games which end on Sunday.

The New York-based Human Rights in China says 24 protesters, Communist Party critics and their family members were detained or closely guarded before the Olympics opened on Aug. 8. Countless others were captured in the months prior to silence critics as thousands of foreign reporters descended on the city.

Dong's wife, Ni Yulan, was jailed in April, when authorities began clearing out activists and others they felt may launch embarrassing protests during the Games in front of a global audience.

In another case, petitioners Wu Dianyuan, 79, and Wang Xiuying, 77, were sentenced to one year of "re-education through labour" after repeatedly applying to hold demonstrations in the areas Beijing has set aside for protests during the Games, Human Rights in China said on Wednesday, citing Wu's son.

The two women, who had planned to demonstrate against their forced eviction from their homes in 2001, may serve their term outside the labour camp but their movements are restricted. They can no longer apply to demonstrate, the organisation said.

None of the dozens of applications to protest in the protest zones has been granted.

Ni was detained for a year in 2002 over filming a controversial home demolition project in her neighbourhood. She also speaks regularly to reporters about issues in China and helps anti-government petitioners get an audience.

She was not planning to protest during the Games, Dong said.

Ni, 48 and disabled from a fight with authorities in 2002, is being held now for "hampering government work", police records say.

Dong says a group of plain-clothed officers illegally entered their house on April 15, cut power and phone lines and destroyed parts of the house.

"They wanted to see us stuck in jail so the Olympics would look better," said Dong.