The union behind a planned five-day-long strike on Southern Rail has called for "urgent talks" with operator Govia Thameslink Railway (GTR). The Rail, Maritime and Transport Workers (RMT) union, which represents the rail guards planning to walkout from 8 August, fears job losses and pay cuts over a plan to operate doors on new trains in conjunction with CCTV.

"RMT officials have already cleared the diaries and are available for serious and genuine Acas talks which is exactly what we have been calling for all along," said Mick Cash, the general secretary of the RMT.

"On top of that we repeat our offer in good faith to suspend action if the company agrees to suspend the planned changes to the safety critical role of the guard and the bulldozing through of the new contracts without agreement.

"That would create the space for talks to take place outside of the pressure cooker. RMT will be at Acas to discuss the full range of detailed issues at the core of this dispute."

GTR has asked mitigation service Acas to facilitate talks with the RMT in a bid to resolve the dispute. Dyan Crowther, chief operating officer of GTR, added: "The RMT's claims we have refused to engage with them are simply not true and we are calling on them to come to Acas and sort this out for the sake of our passengers.

"Passengers have been suffering daily disruption ever since the RMT began this unnecessary action and should not be forced to suffer five days more, all because the RMT is refusing to work with us and modernise the railway for the benefit of our passengers.

"We have guaranteed all our on-board staff a job, as valued members of our future operation, with no reduction in salary.

"We value the work of our staff, who are trying their best to deliver service levels that passengers expect. The sooner we can introduce the essential modernisation that our railways desperately need, the sooner we will address the current capacity and performance issues and deliver a better service for our passengers."

GTR has cancelled 341 trains per day over July in a revised timetable designed to boost customer experience and in reaction to staff sickness levels.