Tram wires are down near the corner of Alexandra Parade and Smith Street, Collingwood, after a truck collided with them on Tuesday afternoon.

The incident is causing additional traffic congestion in an area already under strain due to the current Nicholson Street road closure.

Yarra Trams has extended tram route 86 bus replacements to cover the area, tweeting: “Due to a truck hitting the overhead wires at Alexander Pde – Buses are replacing Route 86 trams between Stop 42 Dundas St and Stop 10 Parliament Stn”.

In a follow up tweet, the public transport operator said the collision had subsequently caused a power outage on the tramline in Clifton Hill.

“The closest that trams are able to get to the area is Stop 42 Dundas St, so we have extended buses to minimise the impact.”

Herald Sun reporter Brianna Travers was one of the first to break the news, sharing an image of the fire on Twitter. Travers reported a truck hit tramlines “causing them to fall and catch fire”.

The Australian Traffic Network tweeted: “Clifton Hill – wires down bothways Alexandra Pde at Smith Street”

According to Broadsheet commercial editor Marcus Teague, tram wires could be seen shaking at the south end of Smith Street, almost one kilometre away from the collision.

"The overhead wires all along Smith Street were shaking up and down,” Teague said. “Like a high wind, only there was no wind."

Updates here.