One person has been seriously hurt in a crash that closed a busy Auckland road.

Another person is also being treated for minor injuries after two vehicles crashed along Great South Rd in Penrose at about 1.17pm today, police said.

Great South Rd is now closed between Walls and Greenpark Rds, Auckland Transport tweeted.

Traffic diversions are in place, with AT warning motorists to allow extra time for the detours.

AT buses 298 and 321 will also be following the detours and miss two stops.

Public transports users should know buses won't be stopping at Stop 7622 - Green Park Rd and so they should instead use Stop 7624 - Penrose Station/Great South Rd.

Similarly buses won't be stopping at Stop 7625 - Green Park Rd with users instead using Stop 7627 - Penrose Station/Great South Rd.