Google has won the first battle in its plan to acquire advertiser DoubleClick, as the Australian competition watchdog announced today it would not block the $3.1bn (£1.5bn) deal.

The search giant still faces inspection from European regulators, who recently extended the deadline for their enquiry from 26 October to 13 November. Antitrust experts at law firm Kirkland & Ellis predict that Google will win its case in the US.

A key consideration in the investigations is the potential ability for the merged company to drive up advertising prices, said the Australian Competition and Consumer Commission (ACCC).

"In reaching its decision, the ACCC noted that Google and DoubleClick are not close competitors in the provision of ad serving," said ACCC chairman Graeme Samuel.

"In addition, the ACCC also took into account the presence of other competitors in this market that would be likely to constrain the merged entity post-merger.

"In this context, the ACCC considered that the merger was unlikely to result in a substantial lessening of competition in an Australian market."

Microsoft claims that Google will control 80 per cent of online advertising if the DoubleClick agreement goes ahead.