Karan Bhatia, vice president of global government affairs and public policy at Alphabet Inc's Google and a former official under Republican President George W. Bush, said in an op-ed published on Monday on Fox News's website that he will tell senators that "Google's products are not politically biased."
He added that the company goes "to extraordinary lengths to build our products and enforce our policies in such a way that political leanings are not taken into account."
To manage billions of searches of hundreds of billions of web pages "we rely on an algorithmic approach and implement rigorous user testing and evaluation before we make any changes to our algorithms," Bhatia added.
US President Donald Trump and some Republicans in Congress have accused Google and other major tech companies of being biased against conservatives but have not offered evidence to support the contention beyond pointing to some anecdotes.
Senator Ted Cruz, who chairs the Senate Judiciary subcommittee holding a hearing on Tuesday with Google, said in April at a similar hearing with Facebook Inc and Twitter Inc that many Americans believe big tech firms are biased against conservatives.
"If we have tech companies using the powers of monopoly to censor political speech, I think that raises real antitrust issues," Cruz said.
Facebook, Twitter and Google have repeatedly denied their platforms are politically biased.
Cruz and Republican Senator Josh Hawley on Monday asked the Federal Trade Commission to probe how major tech companies curate content, saying "Google, Facebook, and Twitter exercise enormous influence on speech."
"They control the ads we see, the news we read, and the information we digest. And they actively censor some content and amplify other content based on algorithms and intentional decisions that are completely nontransparent. Never before in this country have so few people controlled so much speech," they wrote.
Senator Mazie Hirono, the top Democrat on the panel, said in April that "we cannot allow the Republican party to harass tech companies into weakening content moderation policies that already fail to remove hateful, dangerous and misleading content."
Last week, Trump said he planned to call major social media firms to the White House for a meeting and said he was asking his administration to explore "regulatory and legislative solutions to protect free speech and the free-speech rights of all Americans.