Prime Minister Scott Morrison has downplayed reports China has suspended lucrative imports of Australian coal.
Chinese steel mills and power plants have reportedly been told to stop using Australian coking and thermal coal.
State-owned ports have apparently been ordered not to offload shipments.
Trade Minister Simon Birmingham confirmed there had been some disruptions to Australian shipments of coal into China, but said there was no evidence to verify a full-blown import ban.
Mr Morrison is confident the Chinese arrangements are not unusual.
"They do have their own coal industry and it is not uncommon from time to time the Chinese government will have domestic quotas to support local production and local jobs in China," he told reporters on Tuesday.
"That is not a new thing ... that is just part of their normal process."
Asked whether Australia could challenge the move at the World Trade Organisation, Mr Morrison said: "The arrangements they put around domestic quotas in coal production is not unusual."
Senator Birmingham said he had been in touch with the Australian coal industry and was seeking a response from Chinese authorities.
The minister has not been able to contact his Chinese counterpart for many months, with diplomatic relations in the deep freeze.
"There have been patterns of things that look like there are some formal quota systems operating," he said.
"But we take the reports seriously enough to try and seek some assurances from Chinese authorities."
Minerals Council of Australia chief executive Tania Constable believes informal Chinese quotas might be to blame but remains upbeat about coal exports.
"The trade with China changes through the year based on a range of factors, including quotas," she told AAP.
"Australia will continue to see demand for its high quality of coal and the medium term outlook remains positive."
China has launched trade strikes on Australian beef, barley and wine in recent months.
A further strike on Australian coal could smash the economy, which is already deep in recession.
Australia is China's largest supplier of thermal coal and exports of coking coal surged by 67 per cent in the first half of this year.
Treasurer Josh Frydenberg said Australia would work to resolve any issues around coal with China.
"We'll do so in a constructive way, we'll do so in a productive way."