Metrolink services between the Etihad and Ashton-under-Lyne were temporarily stopped following a crash on the lines in Tameside.
Traffic on Edge Lane in Droylsden was partially blocked as a result of the collision, which involved three vehicles.
Police were called to the scene at 3.45pm on Wednesday, there were no reported injuries.
Trams are now operating again, but there are delays in both directions on the Ashton-under-Lyne line.
Motorists are also being advised to avoid the area if possible.
Read more of today's top stories
According to Metrolink, customers can use their tickets on several bus services instead.
It said: "Due to an earlier road traffic collision we are currently experiencing minor delays on the Ashton-under-Lyne line.
"Services travelling in both directions between Piccadilly and Ashton-under-Lyne are affected.
"Customers can use their tickets on the 216 and 217 buses.
"Metrolink apologises for any inconvenience this may cause."
Stagecoach also warned of delays to its services.
It tweeted: "216/230/231 Srv Due to a police incident involving a tram on Ashton New Rd congestion around Droylsden causing delays up to 20 mins."
Tameside Highways added: "Reports are coming in of an RTC at Edge Lane Droylsden please avoid the area for the time being. Expect delays."
