More than 30,000 people took to the streets in Hong Kong on Sunday, urging the Hong Kong Special Administrative Region to cancel a controversial patriotic education course it plans to introduce in local primary schools this September.

Organized by the Alliance of Anti-patriotic Education in Hong Kong, the protest started at 3 pm at Victoria Park. The protesters, including parents with baby strollers and young adults, marched on to government offices, holding banners saying "Stop the red brainwashing." The number of protesters reached 32,000 at its peak, Radio Television Hong Kong quoted the police as saying.

The patriotic education program is designed to introduce Hong Kong students to the political system and historic background of the mainland.

Some Hong Kong people are worried that the course will "brainwash" their children from an early age and hamper their independent thinking, according to Hong Kong media.

"We have around 3,000 teachers responsible for the program in Hong Kong. How can we control 3,000 teachers to teach the same method and same content? I don't think people should worry about the problem of brainwashing," Ng Hak-kim, chief officer of Hong Kong Education Bureau, told the Ta Kung Pao newspaper.

Ng told the Hong Kong media that he supports Hong Kong people's core values which are important to them. "It's my responsibility to stick up for them. Any brainwashing would violate our values, and be completely unacceptable."

Ng met with parent and teacher groups in Hong Kong on Saturday to discuss the patriotic education program. He told Wen Wei Po that the Hong Kong government would be open to different opinions and will continue communicating with schools and parents.

Chen Junli, professor at the Center for Studies of Hong Kong, Macao and Pearl River Delta of  Sun Yat-Sen University in Guangzhou, told the Global Times that the main purpose of the patriotic education program is to widen Hong Kong students' view of the mainland's political system.

"People need to respect a political system that is different from theirs," Chen said.

Zhang Dinghuai, a professor at the Contemporary Chinese Politics Research Institute at Shenzhen University, told the Global Times that there are historical reasons why some Hong Kong people oppose the patriotic education program.

"When it comes to patriotic education, people's first thought immediately goes to the Cultural Revolution (1966-76)."

A recent poll found the number of Hongkongers who consider themselves Chinese hit a 12 year low at 17% in 2011.