A teenage Russian model who died after working a 13-hour day in China may have been murdered, according to reports.

Vlada Dzyuba, 13, collapsed following a gruelling modelling assignment in Shanghai, with her death initially blamed on exhaustion, septicaemia or meningitis.

The teenager is said to travelled to China without medical insurance for her three-month modelling stint and was "too scared" to request medical help.

Initial reports of an autopsy are now suggesting the girl died as a result of "biological poison" that may have been deliberately administered.

According to Russian magazine Life, the autopsy adds: "The origin of the poison has not been established yet.

"Vlada could have been bitten by a mortally poisonous insect, she could have eaten something, or she could have been deliberately poisoned."

The autopsy adds that further tests will be required before any firm conclusions can be reached on the cause of Vlada's death.

The official Chinese report said she died from septicaemia "with multiple visceral organs damaged, liver dysfunction and renal insufficiency".

The Russian Investigative Committee opened a criminal case into her death in October. It is believed one of the lines of inquiry into whether her "personal curator" Dmitry Smirnov delayed seeking medical care for the teenage model when she became unwell.

The teenage model reportedly suffered chronic meningitis "compounded by severe exhaustion" and remained in a coma for two days before she died.