Two infrastructure funds were today set to announce they have raised $10 billion (£5.06 billion) as interest surges in a sector covering everything from toll roads to water and gas utilities.

The largest fund is run by Credit Suisse's private-equity group Global Infrastructure Partners (GIP), which co-owns London City Airport, waste management group Biffa and has invested in Great Yarmouth port. It has reportedly raised $5.6 billion.

Another fund of Morgan Stanley is said to have raised $4 billion, against expectations of $2.5 billion.

Infrastructure assets are becoming more popular as the credit crunch bites, with many private-equity investors seeing them as providing long-term stable income flows.

GIP's fund is backed by founding investors Credit Suisse and General Electric, which each put in $500 million.

GIP says the fund intends to increase returns by improving the operational performance of its portfolio companies.

Morgan Stanley, which owns assets around the world including Venice Airport and the Port of Montreal, invested some $400 million of its own money in its fund.