John Coggan, 61, was at the steering wheel at two minutes past one this morning as they unofficially went past the magic 500-hectare mark.

The planting rig kept working flat out though on the Coggans' Westmar district property as the team completed the necessary 24-hour shift, which was due to end at five minutes to 12 today.

At the end of the 24-hour period independent adjudicators will verify the final world record that has been set and will confirm whether all the conditions of the Guinness World record guidelines have been met.

Mr Coggan says while it's still unofficial he's confident they have the world record in the bag.

At 3:30 this morning they had covered 600 hectares. By 5am it was 655ha.

Mr Coggan says based on their current planting rate they could set a new world record of up to 900ha.

"We now have the chance to set a Guinness World Record that will take some beating," he said.

He, his son, Phillip, and their workmen, Les Bruce and Stephan Wall, have made a dynamic team.

"We've been filling up with seed in six minutes - that's pretty quick," he said.

There have been a few issues such as flat tyres and the need for a quick oil change but Phillip Coggan says they've found a way to conquer the challenges and have only lost around half an hour.

"The machinery has performed really well the whole rig has been a great advertisement for Australian made products," he said.

The Coggan's planting rig consists of a non-modified 120-foot Multiplanter.

One of the largest of its type in the world it is manufactured by Multi Farming Systems at Banana in Queensland.

It is coupled with a 12,000-litre Simplicity Air Seeder made in Dalby and pulled by one of the largest John Deere Tractors, a 9630T, which has 530 horsepower.

John Coggan says with the machinery they've got he was always confident they would do well.