Iron-ore futures rebounded strongly on Monday, with the Singapore benchmark climbing back above $100/t after a downbeat start to the week, buoyed by hopes of improvement in demand for steel in China.

Expectations for fresh stimulus measures have grown following a surprise contraction in China's manufacturing PMI and a slowing growth momentum for service activity in April, which provided further evidence of an uneven recovery for the world's No. 2 economy and biggest steel producer.

"Disappointing construction, manufacturing, and now even services PMI will have given the government serious cause for concern," Navigate Commodities managing director Atilla Widnell said.

China's housing regulator, for one, has tightened governance of real estate agents by ordering them to lower commissions, which Widnell said was a move that could be construed as an attempt to support the struggling domestic property sector.

Iron ore's most-traded June contract on the Singapore Exchange rose as much as 7% to $105.70 a tonne, after shedding 1.7% to $97.05 earlier in the session.

On China's Dalian Commodity Exchange, the steelmaking ingredient's benchmark September contract ended daytime trade 5% higher at 721.50 yuan ($104.33) a tonne, regaining some ground after hitting a five-month low on Friday.

Meanwhile, steelmakers in Fengnan district of Tangshan city, China's top steel-producing hub, have been officially required to roll out a reasonable annual production plan, and make greater efforts to limit this year's output at not more than the 2022 level, according to an official document seen by Reuters.

That raised concerns about steel supply eventually becoming tight, pushing futures higher, which also provided a boost to iron ore prices, analysts said.

Rebar on the Shanghai Futures Exchange SRBcv1 rose 4.2%, hot-rolled coil SHHCcv1 climbed 5.1%, and stainless steel SHSScv1 gained 0.9%.

Coking coal DJMcv1 and coke DCJcv1 on the Dalian exchange also reversed early losses, advancing by 6.8% and 6.3%, respectively.