China is set to double its investment in Iranian infrastructure projects, Iran's Mehr news agency reports.
China has raised its quota for Iranian projects to $52bn (£33bn) from $25bn the report said, quoting Iran's deputy minister for energy, Esmail Mahsouli.
Water, electricity, oil and gas projects will all benefit from the extra financing, Mr Mahsouli said.
Iran has turned to China, Russia and Turkey for financing as Europe and the US have strict sanctions on the nation.
The US has an almost total economic embargo on Iran, while the European Union tightened up its sanctions in 2012, particularly targeting the energy and banking industries.
The US, the EU and other nations suspect Iran of developing atomic weapons and have imposed sanctions over that threat.
Iran says its nuclear programme is only for civilian use.
It is holding talks with world powers aimed at reaching a deal over its nuclear programme.
Negotiators meet in Vienna this week, ahead of a deadline to reach a deal by 24 November.
The US says it will unblock $2.8bn in frozen Iranian funds, in return for Iran continuing to convert its stocks of 20%-enriched uranium into fuel.