Workers at Google Ireland, the search group's European sales hub, earn less than half the £160,000 average wage of colleagues in London - despite the British sales team only providing a supporting role to their Irish counterparts, The Guardian reported.
Google bosses will be grilled by parliament's public accounts committee this week over how they have managed to continue with their controversial Irish tax structures in the face of repeated promises from politicians to close these arrangements down.
The relationship between Google sales teams in London and Dublin are likely to be at the heart of MPs' questioning.
Google Ireland booked £5bn in sales from UK advertisers last year, but paid no tax in the UK. The search group's controversial corporate structure means the UK subsidiary provides "marketing services" to Google Ireland. Meanwhile, UK customers buy advertising exclusively from the Irish company.
Four years ago, Matt Brittin, Google's European sales boss, told MPs that staff in the UK only "encourage" British advertisers to buy from the search group, but the advertisers ultimately buy "from our expert team in Dublin."
He stressed: "Anybody who buys advertising from us in Europe buys from Google in Ireland from our expert team."
Despite the expertise of Google Ireland's workforce, latest accounts show the business paid 2,577 staff wages totalling €244m for 2014 - giving an average wage of €94,590, or £72,783.