Westgate has closed due to an “emergency”.
Travelchoice Peterborough, which provides travel information in the city, tweeted: “Emergency road closure on Westgate, disruption to buses expected, please check your operator for further details.”
Peterborough City Council said the road had been closed for Anglian Water to carry out repairs.
An Anglian Water spokesman said the road had been closed due to a sunken manhole cover which has been repaired.
However, due to the concrete needing to be set the road will remain closed over the weekend.
The city centre road was due to be closed earlier this week between Broadway and Park Road while water works took place.
Westgate was also previously closed back in February due to a burst water main outside Beales, forcing emergency repairs.