"There was also some argumentation between the co-pilot and the pilot and captain relating with the speed and flaps," he told the Nine Network.
The Garuda Airlines aircraft with 140 people on board overshot the runway in the central Java city of Yogyakarta on March 7 and burst into flames, killing 21 people including five Australians.
Survivors of the crash have described how the aircraft approached the runway at a "crazy" speed.
"The co-pilot is a young pilot with just about 2,000 flying hours and the captain, is experienced, having enough experience, more than 15,000 flying hours," he said.
Investigators said last month they had been able to download the last 30 minutes of the crew's conversations after the black box cockpit voice recorder, which was badly burnt, was sent to the United States.
Asked if the co-pilot wanted the captain to go around, he said: "Yes, I think."
Kurniadi said the flaps did not jam, and it appeared it would have been possible at that stage to go around, but it was not known why the pilot chose to land.
The investigation was expected to be finalised in a month.
Indonesia has suffered a string of transport accidents in recent months, including an Adam Air aircraft that disappeared in January with 102 passengers and crew on board and a ferry sinking in late December in which hundreds died.