LONDON, May 8 (Reuters) - Google parent Alphabet

has urged a London tribunal to block a mass lawsuit

which accuses it of abusing its dominance in the online

advertising market, in the latest case to focus on the search

giant's business practices.

The lawsuit seeks damages of up to 13.6 billion pounds

($16.9 billion) on behalf of publishers of websites and apps

based in the United Kingdom, who say they have suffered losses

due to Google's allegedly anticompetitive behaviour.

Lawyers for Ad Tech Collective Action asked the Competition

Appeal Tribunal (CAT) to certify the case to proceed towards a

trial at the start of a three-day hearing on Wednesday.

Google, however, said the case was incoherent and did not

explain how alleged anticompetitive conduct had supposedly

caused losses to the publishers.

Ad Tech Collective Action's lawyer Robert O'Donoghue said

the London lawsuit was "the latest in a series of major

set-preferencing abuse cases involving Google".

The case comes amid ongoing probes by regulators into

Google's adtech business, including by Britain's Competition and

Markets Authority and the European Commission, which O'Donoghue

said was concluding imminently.

O'Donoghue also referred to two multibillion-euro fines

levied on Google by the European Commission, over its online

shopping search service and the requirement to pre-install

Google Search and its Chrome browser on Android mobile devices.

Google is also fighting two lawsuits in the U.S., one

brought by the Department of Justice and another by Texas and

other states, accusing the company of anticompetitive conduct.

The company "strongly rejects the underlying allegations

against it", its lawyers said in court documents for the CAT

case. "Google's impact in the ad tech industry has been hugely

procompetitive."

Ad Tech Collective Action's proposed lawsuit is the latest

against a tech giant at the CAT, which already this year has

certified a $3.8 billion case against Facebook parent Meta

and a nearly $1 billion case against Apple ( AAPL ).