EU not investigating Google's tax deals

The EU regulator investigating whether Alphabet unit Google is abusing its market power has not extended its scrutiny to the tech giant's tax deals with national authorities across Europe, the bloc's antitrust chief says.

Margrethe Vestager, who in recent months ordered Apple to pay up to 13 billion euros ($A20 billion) in back taxes to Ireland and Starbucks up to 30 million euros to the Dutch tax office, said Google was not on her radar for now.

"So far, no, we have nothing formal on that one," Vestager told reporters.

She said she had not received any formal complaint from the Scottish National Party which in January sent a letter to the European Commission concerning Google's 130-million-pound ($A210 million) back tax deal with British tax authorities which some British politicians criticised as a derisory amount.

Vestager also defended the slow pace of the Commission's antitrust cases against Google, saying she wanted the shopping case to be water-tight.

This first case has dragged on since 2010 when her predecessor kicked off the investigation.

"I am as sorry as you and everyone else that antitrust work is taking a lot of time," she told European lawmakers earlier on Monday.

"But it is also a sign that this is a case that is building in its strength as well as a case which is of course strictly following our procedures to make sure that also here we build up the rule of law."

Vestager said she did not know when she would issue a decision but the case was a very high priority for her.

In the shopping case, Google has been accused of favouring its shopping service over those of rivals in internet search results.

It has also been charged with blocking rivals in online search advertising and doing the same with dominant Android mobile operating system.

The Commission has warned the company of hefty fines in both the shopping and Android cases and changes in its business practices if it is eventually found guilty of wrongdoing.