People being treated after being hurt in a stampede in Shanghai's riverfront during New Year celebrations STR/AFP/Getty

A stampede that left 36 people dead during New Year's Eve in Shanghai was not caused by fake money being thrown from a building, police said.

Shanghai police said CCTV footage showed money being thrown from a bar in the building by the Bund river – the city's famous waterfront – which people picked up, but the incident happened after the stampede.

Initially, state media said people rushed to pick up the money that looked like $100 notes.

Witnesses also said the problem started away from the area where the fake money was thrown, as people were trying to access a platform overlooking the river where large crowds had gathered to watch a light show.

The country's state-run news agency Xinhua reported people had been trampled on after they fallen down on the steps up to the platform.

"We were caught in the middle and saw some girls falling while screaming. Then people started to fall down, row by row," a witness told Xinhua.

China's President Xi Jinping has ordered an immediate investigation into the cause of the stampede, telling governments across the country to put in procedures to prevent a similar disaster from happening again.