Global leaders have made a step towards properly taxing multinational tech giants like Facebook and Google.

G20 finance ministers have agreed to work together on shared rules to close tax loopholes used by the companies.

Auckland University tax expert, Crag Elliffe, told Mike Hosking the main tension is between the need to clamp down on the global companies, while still allowing countries to run their economies their own way.

He says the strategy will be finely balanced between those two approaches, but it's not clear if - or when - it will be finalised.

In the meantime, New Zealand's government has followed the lead of Britain and France, by announcing a digital services tax of its own.