UPDATED: 6.39PM A crash on Auckland’s Southern Motorway is adding to rush-hour congestion in the country’s biggest city.

The New Zealand Transport Agency said the crash was blocking the citybound right lane before the Mt Wellington off-ramp.

The agency said motorists should expect delays and take care.

Meanwhile, trains are now running with a 20 minute between Britomart and Papakura after a freight train breakdown earlier caused delays.

Auckland Transport said the train had broken down at Te Mahia in Manurewa.

Auckland Transport said rail replacement buses were running between Homai and Papakura. However, it later said the rail operator had been unable to arrange replacement buses.

Meanwhile, a truck breakdown was causing delays north of Auckland tonight.

The New Zealand Transport Agency said the truck had broken down in the southbound lane of State Highway 1 near Pohuehue, between Puhoi and Warkowrth.

The breakdown caused long delays to traffic in both directions until the truck was cleared.

However, the agency said motorists should still expect delays as congestion eased.