Passengers were left sweltering inside a plane during a two-hour flight delay in China.

Video shows disgruntled travellers fanning themselves inside the cabin of the Boeing 787 Dreamliner without air conditioning while waiting for Juneyao Airlines flight HO1851 to depart from Shanghai Hongqiao Airport on July 3.

The flight was scheduled to leave for Guangzhou City in Guangdong province at 6:10 pm local time but was delayed twice due to thunderstorms.

Local media reported that a woman allegedly fainted due to the heat, after which the other passengers were allowed to disembark and wait at the gate to reboard.

In a statement issued on July 4, Juneyao Airlines said: 'Considering that the air conditioning cooling capacity on one side of the aircraft was weak, while the passengers were waiting to take off, the crew opened the aircraft door and arranged for the bridge-mounted air conditioner to continuously supply air to cool the aircraft.'

It added that airplane doors were opened for ventilation and ice water were provided to the passengers before they were finally allowed to disembark from the plane.

Snacks and drinks were distributed while they waited to reboard.

The statement continued: 'We once again deeply apologise for the discomfort caused by this incident to the passengers. We will continue to strengthen our support capabilities and improve communication and coordination. We are always striving for the passengers' travel comfort and safety.'