Over the weekend, top G20 finance officials agreed there was an urgent need for the introduction of a digital tax.

Talk of a new tax on the likes of Facebook, Apple and Google have grown in recent years, as many countries feel they pay relatively little tax on their massive revenues.

The need for such a tax was underlined by a draft memo from the G20 on Saturday - however very little of real substance was added to the discussion.

"Nothing new was agreed," said Cormac Kelleher, international tax partner at Mazars. "While it's good press and it sounded good, the reality is that actually came back to March 2017 when the G20 gave the OECD the remit, or the job, to actually start looking at this."

Mr Kelleher said there has been a number of updates on that work since then, including a consultation earlier this year, and the G20 memo has little impact on that.

"There is work ongoing at the moment, so what the G20 has said was stuff we had known or expected," he said. "But what it really does show is that it's still at the top of their agenda and it will get looked at sooner rather than later."

There is also some degree of a timeline emerging in terms of when this shifts from talk to actual implementation.

The OECD is required to deliver a final report at some stage in 2020, however Mr Kelleher believes this will come at the earlier part of the year.

"Initially it was supposed to be parked until 2020 and work was supposed to start then, but the OECD felt it was so urgent that they actually accelerated it and started looking at it in 2018," he said.

"My guess is that it will be sooner-rather-than later... especially when we already see countries like the UK and France going on their own and introducing their own taxes."

This is creating an issue, according to Mr Kelleher, as each country is levying different rates and using different methodologies. That includes a flat tax on turnover in some cases - which is not recognised by tax treaties with other countries.

And the method of imposition is a major part of what is slowing the rollout of an international digital tax standard. While G20 countries - and many others - agree on the need for a digital tax, there is far less unity on how it is applied.

Some believe it should be charged where value is created - in other words, where a company has its headquarters or its major research and development operations. Others, though, feel that it should be applied at the point of sale. That is a debate that has not yet been resolved.

"The US are having serious difficulties with this [a charge at the point of sale]," Mr Kelleher said. This is extra tax, it's a real cost and they're not getting credit for it."

As the international headquarters to many of the firms in question, Ireland would also suffer from a digital tax that was charged at the point of sale, as opposed to the point of value creation.

However official figures suggest that the impact, while not small, would not be dramatic in the grand scheme of things.

"Revenue have done numbers on this and it's estimated that it will cost us, in terms of tax take, about €160m per annum," Mr Kelleher said.

"It's a big number, but in the grand scheme of things and in terms of our overall corporate tax take, it's not a huge number. It's a manageable number," he added.