US venture capital funding surged in 2014 to the highest levels since the dot-com boom, industry surveys showed.

Venture capitalists poured $48.3 billion into 4,356 deals in the past year, an increase of 61 percent in dollars and of four percent in deals over the prior year, according to research released Friday by PricewaterhouseCoopers and the National Venture Capital Association.

Internet firms captured $11.9 billion, the highest level since 2000, according to the report, while the software industry attracted $19.8 billion in 1,799 deals in 2014.

PwC's Mark McCaffrey said the year was marked by two deals topping $1 billion and more than 40 "megadeals" of more than $100 million.

"In addition, there's been an influx of private equity investors at a level we've not seen previously," McCaffrey said in a statement.

"As a result, entrepreneurial companies are capable of disrupting entire industries and leveraging investment dollars to expand to the global markets.

"With the continued economic conditions, we would expect venture capital investing to be positioned to continue strong levels of investing in 2015."

A separate report by the research firm CB Insights this week found $47.3 billion in funding across 3,617 deals, with funding growing 62 percent from 2013 levels.

"A mix of traditional VC money coupled with corporate VCs, hedge funds, private equity investors and even sovereign wealth funds created a potent cocktail in 2014, lifting funding levels to the highs seen during the dot-com boom," CB Insights said.

"2014 ended with a bang on the funding front as VC-backed deals hit $7.1 billion in the final month of the year. The massive funding figure was largely driven by mega tech deals to companies including Uber and Snapchat."

The CB Insights report said funding to the mobile sector doubled to $7.8 billion for the year, led by huge investments in firms including Uber, Snapchat, Instacart, and Square. It said health care venture funding jumped to $8.2 billion in 2014.

According to CB Insights, the largest venture firm investing last year was New Enterprise Associates, followed by Andreessen Horowitz.