All waiting rooms at its railway stations have been shut until further notice.
A spokesman however said they may be reopened in bad weather.
All ticket barriers have also been opened, meaning passengers do not have to pass paper tickets through the barriers or present them to staff.
It's furthermore suspended the issuing of penalty fares until further notice.
Customers will still need a ticket to travel and should buy before they board trains at stations or online.
The company is only accepting card payments at the moment but cash payments can only be made at a small number of ticket machines.
Mark Powles, commercial and customer director at Northern, said: “Our trains and stations remain open for business to help key workers get where they need to be across the north of England.
“For those who have to make essential journeys, and for our staff who continue to work across the network, we want to make the railway as safe as possible.
“The measures we have introduced further limit person to person contact and help staff and passengers follow the advice from government on social distancing.
“Our ticket offices remain open to provide help and advice to passengers.
"Customers who want to pay by cash will be asked to use ticket machines if they are available.
“These are unprecedented times for the rail industry and everyone at Northern would like to thank our customers for understanding.”