Chinese iron ore and steel rebar prices jumped on Thursday, with iron ore snapping a three-day losing streak, pulled higher by base metals amid renewed hopes that government spending will spur demand from construction and infrastructure.

Iron ore with 62 per cent content in Qingdao, which hit a two-year high of $US83.58 on December 12, rose 2.2 per cent to $US78.93 a tonne on Thursday, according to Metal Bulletin.

Non-ferrous metals from copper to aluminium rose after China unveiled late on Wednesday a $US115 billion railway construction plan that would require massive amounts of wiring and rail track.

The most-active rebar contract for May delivery on the Shanghai Futures Exchange settled up 2 per cent at 2953 yuan ($US429.20) per tonne. It hit a six-week low on Wednesday.

Traders continue to focus on Beijing's efforts to crack down on outdated capacity in a bid to curb excess output. On Tuesday, the government said it would impose higher power prices on mills using outdated equipment.

Iron ore on the Dalian Commodity Exchange finished up 1.8 per cent at 548.5 yuan a tonne.

Domestic stocks remain at 2 1/2-year highs, rising by 90,000 tonnes last week to almost 111 million tonnes.

"Given stock levels in the country, and supply coming online over the course of 2017, we continue to hold a bearish view towards iron ore," said Rabobank analysts.

A prolonged bout of toxic smog across the north of the country has renewed concerns about slower manufacturing output, forcing hundreds of factories including steel mills to scale down production or close completely.

Separately, Brazilian iron ore exports to China increased by 15.8 per cent in 2016 compared with the previous year, according to figures released by the country's foreign trade ministry, MDIC, reported Metal Bulletin. Shipments came to 214.56 million tonnes, up from 185.23 million tonnes in 2015.