Google's report on the first quarter of 2008 shows an unexpectedly strong start to the year for the search giant.

The company logged US$1.31bn in profit between January and March on total income of US$5.19bn.

The US$5.19bn in revenues marks a 42 percent increase from the first quarter of 2007, and a seven per cent rise on the last quarter of 2007.

The majority of Google's income came from its own properties. Sites owned by Google accounted for US$3.4bn, making up 66 per cent of the company's total revenues.

AdSense accounted for nearly all the remaining income, bringing in US$1.69bn and accounting for 33 percent of revenues.

Some 51 percent of income came from outside the US, including US$803m from the UK.

Google credited a portion of this to the weak US dollar, estimating that around US$18m of its revenues were due to the favourable currency rate.

Chief executive Eric Schmidt said that the integration of DoubleClick into Google's advertising platform would "increase value" for advertisers and partners.

Investors shared Schmidt's rosy outlook on the earnings. Google stock rose 20 per cent following the release of the report, the largest single-day surge on the stock market for the company since its IPO in 2004.