A fresh round of tube strikes will be launched in February if London Underground does not produce “serious proposals” for extra station staff at talks, the RMT has warned.

The union, which represents about 80% of the 3,700 station staff who went on strike earlier this week, said it would call further, escalated strike action from Monday 6 February unless its demands on staffing and safety were met.

The most recent strike closed most tube stations in central London on Monday and left the roads gridlocked as commuters struggled to find alternative transport.

All parties called for talks after the strike, in a row over more than 800 job cuts brought in – along with the ticket office closure programme – by the previous mayor, Boris Johnson. Both London Underground and the TSSA union, which represents the rest of the staff, have urged a negotiated solution.

While Transport for London (TfL) has acknowledged that the job cuts went too far, and offered to reinstate 200 posts this year, the RMT said it had yet to propose plans that could satisfy its members.

Mick Cash, the RMT general secretary, said: “RMT members on the London Underground stations see day in and day out the toxic impact of the job cuts programme and they are reporting back that it is horrific.

“It has now also been shown that at management level there is agreement with the union that the cuts have been a disastrous mistake and that the staff need to be put back on the stations. We now need a move away from the piecemeal and incremental approach to tackling this crisis and for LU to come forward with a serious package of proposals.

“With the constant overcrowding on stations and platforms it is only a matter of time before there is a major tragedy if we don’t act decisively.”

TfL had indicated that it expected fresh strike dates to be set before talks would resume. Cash said the date gave “ample time” for London Underground to make proposals to kickstart negotiations, and the union remained available for talks.