Coal was Australia's most valuable export in 2018 with China,Japan and South Korea the main customers.
S&P Global Platts'Asian thermal coal expert Michael Cooper said private buyers were taking advantage of restrictions driving down coal prices.
"Chinese buyers are looking for May-loading Australian cargoes,and some have booked[low grade] Australian at about $US57 a tonne,though sources interpret this as a risk-taking move essentially banking on the import restrictions for Australian cargoes being lifted in late May,"Mr Cooper said.
"Market sources tell us they can see little economic reason for Chinese buyers to avoid Australian thermal coal. Therefore,some market sources have arrived at the conclusion that there may be more at play in the import restrictions for Australian coal than economic issues."
Chinese analysts acknowledged Australian coal had faced customs restrictions which another major supplier,Indonesia,had not.
"We are watching whether the policy restriction on Australian coal will be lifted in May as the demand and supply have reached a certain degree of balance,"said Shanghai MySteel's assistant editor of coal and coke,Mo Minjie.
"However,as Shaanxi and Inner Mongolia,two major coal production provinces,release their productivity,it's hard to say if the restriction will be lifted."
He said customs clearance for Australian coal was taking from 40 days to two months.
Reports that Chinese power plants are specifying the lower quality coal in tenders was likely due to the warmer weather,he said.
Piles of coal sit near port facilities at the Qinhuangdao Port.Credit:Bloomberg
"In low season,they mostly burn low-grade coals and in winter heating season,they will burn high-grade coals. This is low season now and also we observed that power plants at coastal provinces are lowering their stockpile,"he said.
As rumours abound among Chinese traders that the customs restriction on Australian coal could be lifted in May,several spot purchases were made for boats unloading in June.
A source,who preferred to remain anonymous,said any change on the restrictions will not come until the end of May.
"Everything is pointing to this being on hold until the end of the Australia election,"he said.
BHP,one of Australia's largest suppliers of thermal coal to China,said the import delays may become the new normal.
"It is unclear exactly how attitudes towards controlling imports will unfold in the medium term,but it seems likely that some form of flexible quota system will be in place for the next few years,"the miner said in its recent commodity outlook.
Thermal coal miners Glencore,Yancoal and Whitehaven Coal were approached for comment.