Flames were visible on the roof of the station and smoke filled the foyer.
"We expect trains to be disrupted on all routes through Nottingham for the whole of Friday 12 January", said East Midlands Trains, which is the main operator at the station.
Nottinghamshire Fire and Rescue Service took this picture of a firefighter tackling the flames on the main concourse early this morning.
"Emergency services are dealing with a fire incident at Nottingham, causing major disruption to trains at the station", National Rail said.
A spokeswoman for East Midlands Ambulance Service said "we are aware of the incident and, at the minute, there are no reported casualties".
At least 60 firefighters are tackling a large fire in a recently redeveloped section of Nottingham railway station. Firefighters said that they were battling a "significant fire".
The incident has caused delays across the local transport network.
There are no reports of any injuries at this time.
The situation is so severe that East Midlands can not yet predict when the station will be up and running again, with trains both in and out of Nottingham cancelled.
Nottinghamshire Fire and Rescue Service tweeted that crews are "working to stop the fire from spreading". Transport in the area will be severely disrupted, with no services going to or from the station. This means we have no service from the Forest to Clifton South or Toton Lane.
- Passengers should visit www.eastmidlandstrains.co.uk for the latest travel information.
East Midlands Trains tweeted: "Please do not travel to Nottingham station this morning as trains will be unable to run and we are unable to provide road support to/from the station".