NEW YORK (CNNMoney.com) - Internet advertising revenue spiked 30 percent to set a new record in 2005, according to estimates released by PricewaterhouseCoopers on Wednesday.

Online ad sales likely topped $12.5 billion last year, compared to $9.6 billion in 2004, the accounting firm said.

Web advertising has grown at a rapid clip, contributing to the growth of several Internet firms. Tech bellwether Google (Research), for example, relies heavily on search-based advertisements to generate revenue.

But there have been concerns recently that click fraud, an illegal practice that fabricates increased traffic for ads and links, may deter companies from advertising online. (Full story.)

The PricewaterhouseCoopers report, however, suggests demand for Internet advertising remains strong.

"With the increase in broadband penetration further enhancing how messages get delivered, we should continue to see a favorable environment for increased Internet ad spending," David Silverman, a partner at the financial services firm, said in a statement.

The PricewaterhouseCoopers study was based on data from the top 15 Internet ad sellers and sponsored by the Interactive Advertising Bureau. The report's final results are expected to be released in April.

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