Rail MInister Chris Heaton-Harris told a meeting of northern political leaders that the "end game" had been reached on what to do with the North's biggest rail franchise after months of poor performance.
He said Transport Secretary Grant Shapps - who said he was "not prepared" to tolerate the commuter line operator's poor performance - would reveal more about the Government's plans when he visits Leeds tomorrow.
After asking for proposals from Arriva, which runs the Northern franchise, Mr Shapps could award a short-term contract to the operator or take it into public hands, via what is known as an Operator of Last Resort.
Mr Heaton-Harris told a meeting of Transport for the North in Leeds: "There is a very detailed legal process that then goes on, with figures going back and forth and things bebing proven and disproved with finances.
"At the end of it the government makes a decision. How long will it take? Not much longer. There is probably a few weeks left in that process. It will be sooner rather than later.
"Whatever the Government then chooses to do there would not be a change overnight in Northern services.
"We have got to be realistic about what is going on with the operating company.
"People with expertise come to us with proposals for what they believe is best. We then make a decision, it takes a few weeks.
"I think we can expect to see quite significant changes very soon. It is worth listening to the Secretary of State when he comes to Leeds tomorrow."
He spoke after being challenged by leaders including Leeds City Council leader Judith Blake and Greater Manchester metro mayor Andy Burnham to take urgent action on Northern rail services.
Bosses at Northern said its poor performance before Christmas was due to "unprecedented" sickness levels among drivers and a failure to deliver major infrastructure schemes which has resulted in a congested network.
Mr Burnham said Mr Shapps, who had been expected at today's meeting but did not attend, had to address the issues urgently.
He said: "2018 and 2019 were terrible years on our railways. We can't let 2020 drift into a similar situation. It has got to be gripped."
Tory Minister Chris Mr Heaton-Harris said of the ongoing rail disruption in the North: "Northern will point at Network Rail not delivering infrastructure improvements in 2018. Everyone can point fingers at everyone else."
He said that in West Yorkshire a train failed to leave the depot before Christmas and trapped lots of other trains behind it, leading to widespread cancellations.
Describing the changes that are due, he said: "We are doing what we need to legally so we don't get sued to high heaven afterwards to make sure we make the right decision for passengers and people who work on these railways going forward.
"Whatever the change is, it will be a long-term project to turn round this franchise, there is lots that needs to be done."