(Recasts with comments from hearing)
WASHINGTON, Sept 17 (Reuters) - The top U.S. antitrust regulators admitted on Tuesday they had wasted time arguing over who would investigate which tech company as they take on major probes of firms like Alphabet's Google for using their market power unfairly.
The Justice Department's antitrust division chief, Makan Delrahim, acknowledged instances where officials' time "is wasted on those kinds of squabbles."
The hearing was a tough one for Delrahim and Joe Simons, chair of the Federal Trade Commission, who were criticized by lawmakers at a hearing of the Senate Judiciary Committee's antitrust panel for overlapping on the probes, and for other matters.
Reuters and others reported in June that the agencies had divided up the companies, with Justice taking Google and Apple , while the FTC looked at Facebook and Amazon .
The Justice Department later said it was opening a probe of online platforms. This led some industry observers to question whether the two investigations would overlap.
"Based on news reports, it sounds like your agencies may be pursuing monopolization investigations of the same companies," said Lee. "I don't think your agencies should be divvying up parts of a monopolization investigation of the same tech company."
Lee asked both men if the process of deciding which agency would investigate which company - formally called the clearance process - had broken down.
Simons said that for the vast majority of matters, it had not.
"I take that as a yes, things have broken down," said Lee.
"I would agree with that," Simons said.
Senator Amy Klobuchar, the top Democrat on the panel, also pressed Delrahim on a decision to probe four U.S. automakers for potentially breaking antitrust law over how they entered talks with California to curb emissions. The probe comes at a time when the Trump administration has battled the state on everything from immigration to census questions.
Under questioning from Klobuchar, Delrahim repeatedly denied that there had been any contact or discussions between the White House and the Justice Department regarding the automakers or anything else related to antitrust.
"There's nothing wrong with these companies individually announcing higher emission standards if they want to," said Delrahim.
Senator Patrick Leahy, a Democrat, pressed Delrahim about chief executives like John Legere, the head of T-Mobile US Inc , who stayed at the Trump International Hotel, near the Justice Department, during some trips to Washington.
"My decisions are not based on the hotel stays of any merging parties," Delrahim responded.
In June, a group of senators asked the government if the president had interfered in a review of the proposed $26 billion merger of T-Mobile US and Sprint Corp.
Klobuchar and Senator Cory Booker, both of whom are running for president and sit on the subcommittee, signed the letter, as did Senator Elizabeth Warren, also a candidate for the Democratic nomination.
The Justice Department approved the deal, but states sued to stop it. (Reporting by Diane Bartz; Editing by David Gregorio and Rosalba O'Brien)