Tube services could be disrupted this Friday as a 24 hour strike by track patrol staff has been announced.

The Rail, Maritime and Transport (RMT) Union confirmed that more than 500 staff would be walking out from 6.30am on February 12 until 6.29am on February 13.

February 5: Weekend tube strike called off but second strike could still go ahead

January 13: Londoners face three tube strikes in next month as Zac Goldsmith challenges Sadiq Khan's pledge to "stop strikes"​

January 11: Tube strikes have more than doubled under current London Mayor says Sadiq Khan

At the same time, 1,500 maintenance workers are going on strike in a separate argument over safety. 

Although services are expected to run as normal, there is a concern that the announcement of track staff joining the strike could lead to more disruption.

Track patrol staff walk the lines during the day looking for faults, so their walkout could mean problems are not fixed until the strike is over. 

RMT General Secretary Mick Cash said: "This dispute is over an outrageous attempt to casualise and undermine the jobs of our London Underground track patrol members through an extension of the use of private contractors. 

"RMT will continue to fight all attempts to undermine and casualise jobs across London Underground as the company looks to cut corners to meet Government austerity targets.

"This union will not accept the undermining of jobs, conditions and safety or the creeping privatisation of functions.

"The union remains available for talks."

TfL advised customers to keep an eye on its Twitter for updates during the 24 hour action, at @TfLTravelAlerts

Steve Griffiths, chief operating officer at London Underground, said: "When we introduce the night Tube we will need some track patrol staff working on Sunday nights rather than Fridays.

"We've given our existing staff the choice whether or not to cover these shifts, which protects their work/life balance.

"No jobs are at risk and contract staff will only be used temporarily, to cover shifts that our employees choose not to work.

"This freedom to choose for our staff is part of our pay and night Tube offer, which the RMT has recommended its members accept. We'll be doing everything we can to ensure this doesn't impact services for customers."