More than 800 passengers on a Eurostar train from Brussels bound for London were stranded for nine hours in northern France on Sunday after a technical failure, the rail operator said.

The malfunction left the passengers without air conditioning or working toilets, with the company saying it had carried out a "long and complex" operation to transfer the passengers to another train.

A Eurostar spokeswoman told AFP the train "came to a standstill with no power on board" on Sunday morning between the northern cities of Lille and Calais.

She said passengers received water and the doors were opened to allow air to circulate.

Several passengers took to social media to vent at the delay and accuse Eurostar of a lack of communication.

In late June, Eurostar trains were severely disrupted after cables were stolen from the tracks in northern France. (AFP)