First West Yorkshire made the announcement at noon on Tuesday, September 3 that Call Lane is blocked due to double parked cars.
All buses are diverting southbound along Boar Lane, Mill Hill, Neville Street and Great Wilson Street.
Bus users are being warned to expect long delays.
Services being affected are:
2, 3, 3A
12, 13, 13A
A spokesman for First West Yorkshire said: "Call Lane currently blocked due to double parked vehicles.
"All buses diverted southbound along Boar Lane, Mill Hill, Neville Street and Great Wilson Street. Couple of buses currently stuck. Delays expected"
As of 12.56pm, services are still delayed but the buses which were stuck have been freed.
A spokesman for First West Yorkshire said: "Call Lane is clear. The HGV causing obstruction has been moved.
"Services back on normal routes but the few buses that got stuck and were diverted now operate with delays between 10 and 20min"