Facebook Ireland paid €2.3m in corporate tax last year, despite earnings of €2.97bn. Its revenues had increased from almost €1.789bn in 2012.

The Irish Independent reports that the Irish wing of the social networking firm represented almost half of its global sales in 2013.

Corporate tax deals offered to multinationals are under scrutiny at European Union and international level.

The paper says the latest accounts for the Irish unit show it recorded pre-tax profits of €7.29m last year, up from pre-tax losses of €626,000 in 2012.

But its Irish corporate tax bill was more than halved from €5.2m in 2012 to €2.3m.

The company bills third party customers for online advertising on the Facebook website.

Facebook moved to a new European headquarters in offices at Dublin's Grand Canal Square earlier, where it says it is planning to double its Irish workforce and employ 1,000 people.

The social network has been based in the capital since 2009 and currently employs some 400 staff in Ireland.