Tube travellers have had their online payment accounts hacked, according to Transport for London (TfL).

Around 1,200 customers attempting to access their online Oyster card accounts have reported being denied access since Wednesday, August 7.

By temporarily taking down the online system, TfL has caused uproar for users as they are unable to check their balance or top up their cards through the website.

While no customer payment details have been breached, it was also made clear that TfL or its services did not think the passwords were leaked by them.

It has been suggested they had been stolen from another website and then were used to login to the Oyster service.

A spokeswoman said the numbers compromised is believed to be small and an initial investigation indicated the Oyster online service had not been compromised.

"As a precautionary measure and to protect our customers' data, we have temporarily suspended online contactless and Oyster accounts while we put additional security measures in place,” said TfL.

"We encourage all customers not to use the same password for multiple sites.”

Around six million people have created online accounts through the Oyster card system.

In the fiscal year of 2018/19 nearly a billion rail, tram and bus journeys were made using Oyster cards, raking in £2.3bn in revenue for TfL.

Any customers affected will be contacted by TfL the incident will be reported to the National Cyber Security Centre and British Transport Police.