SAN FRANCISCO – Google Inc.’s quarterly lobbying expenses eclipsed $1 million for the first time during the summer as the company tried to build on its dominance of Internet search and expand into other markets.

The company spent nearly $1.1 million trying to influence lawmakers and regulators in the third quarter, a 50 percent increase from the July-September period last year, according to a recent disclosure statement.

Google’s lobbying budget has been steadily rising during the past year even as it tightened its belt in other areas to bolster its earnings during the worst U.S. recession in 70 years.

Through the first nine months of this year, Google’s lobbying costs came to $2.9 million, a 41 percent increase from the same time last year. That contrasted with a 2 percent decline in Google’s companywide expenses during the same period.

Convinced the worst is over, Google’s management last month said the company intends to increase its spending again on technology development, computers and acquisitions. The executives didn’t indicate how the loosening purse strings will affect Google’s lobbying costs in coming quarters.

The recent uptick in Google’s political spending has come as the company has been muscling into new markets, including telephones, business software and electronic book sales. At the same time, Google has been steadily increasing share of the lucrative search market; it fields nearly two out of three every search requests in the United States.

Google’s success and ambition have raised concerns about its growing power, attracting more scrutiny.

Last year, Google scrapped a proposed Internet search partnership with rival Yahoo Inc. to avoid a legal showdown with the Justice Department, which asserted the alliance would have broken federal laws seeking to preserve competition.

The Justice Department also has raised objections to another agreement that would give Google the digital rights to millions of out-of-print books. Google is negotiating revisions with U.S. authors and publishers in an attempt to persuade the Justice Department that the deal won’t create a cartel that could drive up the prices of electronic books.

Google also lobbied Congress and the Federal Trade Commission about regulations affecting online advertising, which provided most of the company’s $17 billion in revenue during the first nine months of the year.

Google CEO Eric Schmidt told reporters last week that his company also wanted to express its support for government grants for the expansion of broadband access.

Overall, he said, the company’s focus in Washington “is to continue to support the greatness of the Internet.”