Dalian and Singapore iron-ore futures edged up on Thursday, after miner BHP Group flagged a continuing production weakness, but gains were capped by Covid-19 concerns and steel production controls in top steel producer China.

The most-traded September iron ore on China's Dalian Commodity Exchange rose 1.6% to 916 yuan ($142.51) a tonne, after two days of losses.

On the Singapore Exchange, the steelmaking ingredient's most-active June contract was up 0.6% at $152.40 a tonne by 03:05 GMT.

BHP, the world's largest listed miner, fell short of estimates for iron ore production for the March quarter, as a pandemic-related labour crunch weighed on its efforts to boost production in Australia's Pilbara region.

The miner also warned June-quarter production was expected to be impacted by lingering worker absenteeism, though it remained on track to meet fiscal 2022 costs and volume forecast.

That adds to supply concerns highlighted by the world's biggest iron ore producer Rio Tinto's lower-than-expected first-quarter shipments report, and Brazilian miner Vale SA's 6% drop in first-quarter iron ore output. 

But the iron ore markets are, at the same time, faced with worries about demand prospects in China, where economic growth is slowing due to Covid-19 lockdowns and authorities have vowed to keep reducing steel output.

"The market was whipsawed by a confluence of factors, including weaker shipments in 1Q22 from major miners, while the demand outlook is overshadowed by China growth concerns and crude steel production controls," ING commodities strategists said in a note.

Steel production controls, however, supported prices on the Shanghai Futures Exchange, with construction steel rebar rising as much as 1.6%, hovering near a two-week high.

Hot-rolled coil added 0.3%, also trading near a two-week peak. But stainless steel slipped 0.3%.

Dalian coking coal climbed 1% and coke advanced 1.3% on tight supply concerns.