China’s President Xi Jinping is on a two-day visit to Pakistan, where he is expected to announce investment of $46bn (£30.7bn).
The focus of spending is on building a China-Pakistan Economic Corridor (CPEC) – a network of roads, railway and pipelines between the long-time allies.
They will run some 3,000km (1,865 miles) from Gwadar in Pakistan to China’s western Xinjiang region.
The projects will give China direct access to the Indian Ocean and beyond.
This marks a major advance in China’s plans to boost its economic influence in Central and South Asia, correspondents say, and far exceeds US spending in Pakistan.
“Pakistan, for China, is now of pivotal importance. This has to succeed and be seen to succeed,” Reuters quoted Mushahid Hussain Sayed, chairman of the Pakistani parliament’s defence committee, as saying.
Pakistan, for its part, hopes the investment will boost its struggling economy and help end chronic power shortages.