Transport secretary Chris Grayling has described more proposed industrial action on Southern as "politically motivated" and "designed to create maximum disruption".
In a letter to Simon Kirby MP for Brighton Kemptown received yesterday, Grayling said: "We cannot allow the unions to dictate how or whether the railways should be modernised or not. They are seeking the right to determine when a train should be cancelled to inconvenience passengers, even in circumstances when this doesn't need to be the case."
In his letter, Grayling also said steps were being taken behind the scenes to make progress. "I will be writing to you later this week with details of a compensation package for Southern passengers," he added.
Aslef, the train drivers' union, announced on Monday that Southern rail drivers had voted in favour of strike action and as a result, walkouts will be held on Tuesday 13 and Wednesday 14 December, Friday 16 December and Monday 9 to Saturday 14 January.
Members of the Rail, Maritime and Transport (RMT) union who work on Southern have also voted to strike on a number of separate occasions over the festive period.
"It's clear to me that the industrial action and the unofficial action that has disrupted the route in recent weeks is politically motivated and is designed to cause maximum disruption," Grayling wrote.
Mick Whelan, the general secretary of Aslef, said: "We have done our level best to try and reach a sensible compromise with Southern in the interests of passengers as well as of staff. We have always been happy to talk to the company because we believe it is, or should be possible to do a deal - as we did with ScotRail in Scotland - but it takes two to tango."
He added that it had always been "a trade dispute" and that it had been the union's policy for "more than 15 years" to try and eradicate driver only operation (DOO) as it feels it's "inherently unsafe".
Mick Cash, general secretary of the RMT union, called Grayling's comments "a pack of lies".
He added: "If anyone's politicising this dispute on Southern rail, it's Chris Grayling and his government."
Grayling had said the introduction of driver controlled operation has already been accepted on the Brighton mainline, with objections raised on its introduction on routes that feed into it.
He added that more than 60 per cent of trains elsewhere on the Govia Thameslink Railway network were operated in this way.
Rail minister Paul Maynard added that "to stop the roll-out of modern trains is ludicrous". He said the trade unions "want to take the rail industry backwards, but we must modernise and move forward if we are going to deliver the service passengers expect".
Last month, it was revealed that strikes and resulting problems on Southern this year have cost £38m, according to operator Govia Thameslink Railway.