The bitter pain of bereavement turned to tears of anger Friday for relatives of the 36 killed in a New Year's Eve crush in Shanghai, as they accused authorities of failing to control the crowds.

Li Juan was only a few metres away from her younger sister Li Na on the Bund when the accident happened on a wide stairway leading to a waterfront promenade.

"It all feels like a dream and I still cannot believe that she is gone," she said, weeping uncontrollably and struggling to get her words out.

The 23-year-old victim worked as an assistant teacher in an early learning centre.

"The government is responsible for the accident," Li said, adding she only saw six to eight police on the staircase. "I couldn't see any other police on the plaza" below, she added, before collapsing in grief on the floor.

The stampede took place as vast numbers of people crammed into a square named for Chen Yi, Shanghai's first Communist mayor.

Most of the fatalities were young women, authorities said, and Li was from one of three families who spoke to AFP Friday about their lost loved ones.

Qi Xiaoyan, a 21-year-old migrant worker, came to Shanghai from nearby Anhui province just four months ago to earn money to support her family back home, her cousin said.

"I cannot imagine something like this would ever happen in a city like Shanghai," said Cai Jinjin, who has lived in Shanghai for 10 years.

"Besides the sadness, I'm more bitterly disappointed in this city."

All but four of the dead on a list of 32 identified victims released by the city government were aged 25 or under, and 21 were female. The youngest was a 12-year-old boy, Mao Yongjie.

He became separated from his mother in the overwhelming flow of revellers, news magazine Caixin reported, and efforts by hospital staff to save his life failed. His mother spent New Year's day crying until she passed out from exhaustion, Caixin added.

The crush is Shanghai's worst accident since a fire in a high-rise residential building killed 58 people in 2010, and a black mark for the commercial hub's international reputation.

The official news agency Xinhua said municipal authorities had been caught in a wave of criticism for "not making effective preparative measures to cope with the crowds that flock the Bund".

- Oldest victim -

The oldest fatality was Du Shuanghua, 37, whose wife told AFP he was the family's only breadwinner and she had not told their eight-year-old son that his father was dead.

Fan Ping showed AFP pictures of the family together on her phone, but struggled to find the one she wanted her husband to be remembered by, before refusing to look at it herself.

Friends who were with Du on the Bund told Fan that her husband was still conscious when he arrived at the Shanghai Number One People's Hospital, where most of the injured were taken. But she never saw him alive again.

Police and security guards prevented relatives from entering the hospital before eventually allowing only two members of each family into a waiting area.

"We waited desperately from midnight the first day to 9:00 pm the next day. The hospital did not give me any updates on my husband until we were told to go to the funeral home to see his dead body," Fan said.

Relatives wailed uncontrollably at a funeral home where some of the bodies were taken, with one woman crumpling with despair almost immediately after coming out with other family members holding her up.

One man said: "My son is in there, I can't believe this happened."

City authorities on Friday raised the number of injured by two to 49, according to a statement. Four were in critical condition, Xinhua said citing hospital sources, and another nine were severely hurt.

People continued to gather at the accident scene, some laying flowers in a government-approved show of mourning.

University student Chen Xiaohang placed white chrysanthemums at the memorial site in memory of the sister of a high-school classmate who died.

"I feel very sad about this and I hope the government will offer better safety controls for events like this," she said.

Shanghai residents also questioned why authorities did not control the crowds, although police said a "more than normal" 700-strong force was present.

"The Shanghai government should take responsibility for the incident. Most of the young victims must be the only child of their families," said taxi driver Xu Jianzhong.

Under China's strict birth control regulations most couples are restricted to a single child.