Halloween revellers party in Shanghai, some wearing costumes seen as a protest against China's policies

Halloween revellers have taken to the streets of central Shanghai, with some dressed in costumes that poked fun at China's strict COVID-19 curbs in a rare showcase of free expression as police looked on.

Celebrations in the Chinese financial hub began on the weekend, culminating on Tuesday in a large crowd of mostly young people that gathered around a popular bar area, according to onlookers and social media posts.

Many attendees wore outfits like monsters, superheroes and mythical characters in Chinese folk tales. 

But some attracted attention on social media for costumes such as blue and white hazmat suits that gained infamy in China last year for being used by authorities enforcing COVID-19 curbs known as "dabai".

Almost a year ago Shanghai was the site of historic protests over China's stringent COVID restrictions that spread to several cities and which were later seen as a trigger for the country's sudden lifting of the policy in December last year.

Some people's costumes are reflective of the social and political issues in China, from past to present.

A post from the famous "Teacher Li is Not Your Teacher" X handle, which is run by a painter and former art teacher from Anhui province in eastern China, showed a person wearing a Winnie the Pooh costume with the caption "Shanghai Halloween".

That's despite Chinese authorities cracking down on anything depicting the bumbling bear due to memes that compare him to President Xi Jinping.

Mr Li became an Internet sensation during the pandemic as he reposted details and footage of protests from citizens across China — skirting censors on the rapidly unfolding demonstrations.

Other photos on social media showed people dressing up as surveillance cameras, carrying boards that illustrate China's falling stock market, and acting figures from China's Cultural Revolution. 

Some party goers also showed up with blank sheets of paper stuck to their clothes, a key symbol of last year's protests, other social media posts showed.

Social media posts from Tuesday and the days before included a man dressed up as Lu Xun, a famous author from the early 20th century whose works have been popular among Chinese youth as they grapple with historic rates of unemployment.

The man recited a work by the author that urged those "who can speak out to speak out", before he was told to leave by a police officer, the video showed.

He also carried a sign that said: "Studying medicine cannot save the Chinese", a famous quote from Lu Xun. 

Reuters was unable to verify the authenticity of the video.

"The 'dabai', COVID-19 testing, A-share market … that Shanghai people dressed up as are all elements that speak to the trauma of the times and traces of history," said one user on China's Twitter-like platform Weibo on Wednesday.

Public critiques of government policies are rare in China, where authorities have been cracking down on free expression.

There was little sign of aggressive efforts to stop the gathering by police, but some people in costumes that could be perceived as subversive were filmed being escorted away.

The Halloween costumes in Shanghai's parade have sparked heated discussion on Chinese social media. 

Some Chinese netizens criticised young revellers of “having a blind faith in foreign things and festivals" on Weibo.

But many young people said they are just having fun and releasing pressure through the celebration. 

“The absurd cosplay of young people is already the lowest cost way to relax and go crazy," a Weibo user said. 

ABC/Wires