A Northern Territory trucking business says mining company Sherwin Iron is struggling to pay its contractors.
Sherwin Iron is developing an iron ore mine at Roper Bar, 200 kilometres east of Mataranka in the Top End.
Alan Birch Transport worked for a Sherwin Iron contractor to cart ore from the mine to the Port of Darwin.
But owner, Alan Birch, says the money wasn't coming through.
"We were working for Balmoral and they were blaming Sherwin Iron," he said.
"We requested payment every week and in the end it took about four months.
"Everyone I spoke to seemed to be having the same trouble - late payments, withholding payments, paying half payments instead of full payments".
The executive chairman of Sherwin Iron, Rodney Illingworth, acknowledges there have been some payments issues, but they haven't been unreasonable.
"There may be some instances where [payment] has been delayed in the past," he said.
"We went through a period, I'm not going to deny it, that cash was pretty tight because production had slowed due to the wet season.
"Obviously there are things outside of our control that delay things.
"We've got debt facilities in place and some of those debt draw downs are reliant on reaching certain milestones like EIS approvals."
Mr Illingworth says the issues are not a sign of Chinese buyers losing interest in iron ore from the mine.
"Chinese buyers are more than interested," he said.
"The support there is phenomenal and the demand is there."
Mr Illingworth says the trucking of iron ore has now stopped because Sherwin Iron has reached its short-term mining limit.
The company is only allowed to mine a 400,000 tonne bulk sample of ore until it gains full environmental approval.
The company expects the last ore from the bulk sample to be shipped this week.