Excerpts of a speech Mark Zuckerberg is to give this weekend reveal the CEO accepts that global tax reforms will mean Facebook has to pay more in different countries.

He's due to speak at a security conference in Munich on Saturday (February 15).

Cross-border tax rules are set to be rewritten after 137 states sought last month to avoid a new trade war.

Amazon, Facebook and Google have strained existing rules because they are able to book profits in low-tax countries like Ireland - no matter where their customers are.

Government officials agreed last month to negotiate new rules for where tax should be paid and what share of profit should be taxed.

Washington has threatened retaliatory trade tariffs because it sees such levies as discriminatory against big U.S. tech groups.

Zuckerberg's speech excerpts gave no further details on tax rates.

In Britain, media reports said Facebook paid just $37.2 million in corporation tax in 2018, despite generating over 2.1 billion dollars in British sales.

Tax officials want to iron out the details and reach a full deal by the end of the year.