A letterbox thief stole pension and credit cards from homes in Newcastle, police say.

The 28-year-old woman was arrested on a train near Maitland about 5.10pm (AEST) on Thursday.

She had credit cards and other government-issued cards printed with different names.

Several of the cards were traced to recent letterbox thefts in the beachside suburb of Merewether.

Police transport command officers were initially tipped off when they allegedly found her in possession of a pension concession rail ticket.

It may have been stolen during a break-in at Merewether earlier this month.

Police charged the woman with 12 offences relating to stolen goods and public transport offences.

She was refused bail and is expected before Maitland Local Court on Friday.