Vauxhall Bridge was closed in both directions amid reports of a 'suspicious vehicle'.
Pedestrians were being stopped from crossing the major bridge in south London due to a police incident.
A vehicle was found abandoned just before 4pm and has been examined by specialist detectives.
The car was left positioned very close to the MI6 building and had its hazard lights on, My London reports.
A nearby theatre - 'Above The Stag' - has also been evacuated 'due to a suspect package' on the bridge.
South Western Railway said trains were not stopping at Vauxhall due to the incident near the station.
The scene has been described by a witness as "worrying," adding that the area is "swarming with police".
Police have since confirmed the vehicle has been deemed as non-suspicious following their investigation.
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Lambeth MPS earlier tweeted: "Police are in attendance in Vauxhall Bridge, SE1 after a vehicle was found abandoned just before 4pm.
"The abandoned vehicle is being examined by specialist officers as a precaution.
"No arrests have been made.
"Temporary road closures are in place.
"Thanks for your cooperation."
The force added: "Vauxhall Bridge will remain closed whilst the vehicle is assessed by specialist officers.
"Buses will be diverted and members of the public are advised to avoid the area."
In a tweet, Above The Stag Theatre wrote: "The theatre has been evacuated by police due to a suspect package on Vauxhall Bridge.
"We are still planning to open at 6pm however we will update this feed as we receive updates."
It later added: "Tonight’s performance of THE GOOD SCOUT will now go ahead at 8pm following the reopening of the general Vauxhall area."
South Western Railway earlier tweeted: "Trains will not be stopping at Vauxhall until further notice due to police dealing with an incident near the station.
"Ticket acceptance in place with Southern between Clapham Junction and London Victoria and London Underground via any reasonable route."
Lambeth MPS has now said: "Vehicle left abandoned on Vauxhall Bridge with hazard lights on and no driver has now been fully assessed by specialist officers and deemed non-suspicious.
"No arrests have been made.
"Bridge will be reopening shortly."