Earlier this week, RMT union members voted in favour of London Underground’s latest offer paving the way forward for the launch of the night Tube.
However, around 1,000 maintenance staff were left out of the pay and conditions deal prompting the union to vote on a new round of industrial action.
General secretary Mick Cash told the Evening Standard: "RMT members are furious at the cynical way that Tube Lines have attempted to tie in attacks on pensions with the offer on pay and night Tube, and our reps for this group of over 1,000 safety-critical staff have unanimously thrown the whole package out.
That position has now been fully endorsed by the union's executive and we are preparing a fresh ballot for both strike action and action short of a strike.”
Cash also said there are “major unresolved issues” over staffing arrangements for the night Tube.
London Underground chief operating officer Steve Griffiths said: "We are disappointed that RMT Tube Lines has rejected this fair and affordable pay offer.
"We made a full and final offer on pay and night Tube to all four trade unions on 21 January, and the majority of RMT members have already voted to accept this offer.
"We have already made plans to meet with RMT Tube Lines next week to discuss their concerns over working arrangements."