UPDATED 1.10PM: Traffic is beginning to recover on Auckland's Southern Motorway, after a bus fire at Greenlane brought it to a standstill.

Firefighters say everyone got off the bus safely, as the flames quickly spread through it.

The burned-out wreck is now being hauled off the southbound side of the motorway, and the traffic backlog is beginning to clear.

Jarron Phillips from the Fire Service said the fire was well involved and they had no reports of injuries.

"We don't know how many were on the bus at this stage."

Earlier, motorists were advised to take alternative routes as southbound lanes on the motorway remained shut.

Meanwhile, traffic is also building north of the city as Aucklanders head out of town for the last weekend of the summer holidays for many.

The New Zealand Transport Agency said traffic was congested from Puhoi to Wellsford heading northbound.

Due to an earlier incident on #SH1 Greenlane, lane 1 and 2 are CLOSED. #ExpectDelays and for more info check: https://t.co/fgcHDovhLq ^MN pic.twitter.com/sRsWqRosVf

— NZTA Akld & Nthlnd (@NZTAAkl) January 6, 2017