Some countries, like Ireland, will get less corporate tax if the process to reform the global system succeeds, the man responsible for leading the negotiations has said.

But Pascal Saint-Amans, tax director at the Organisation for Economic Co-Operation and Development (OECD) said those countries would gain in other ways.

"If they get a bit less in terms of revenue, they should get more in terms of certainty," he told RTE News during a visit to Dublin.

"What does that mean? Certainty that other countries would ensure that we do not have too much dispute, too many disputes, if there are disputes there is a way of solving them so that at the end of the day we eliminate double taxation."

Mr Saint-Amans said he accepts the process is stressful for some countries and there is a lot at stake.

But he cautioned that if there is no agreement, there will be chaos that would harm everybody, caused by tax and trade retaliation measures, as countries protect what they think their sovereignty is.

If for example other countries follow France by implementing a digital tax unilaterally, he said, then countries like Ireland could be impacted.

However, with an agreement, some revenue might be lost but a country like Ireland would still be part of an international community with some kind of policed rules that all countries accept together.

Mr Saint-Amans urged Ireland to continue to engage with the latest phase of the international tax reform process, as it had done with the earlier Base Erosion and Profit-Shifting stage.

But he also criticised some of the pace of change here.

"Ireland had been constructive, positive, a bit slow sometimes, like dismantling the double-Irish, with a sunset clause in 2021 which is a bit far, but still a constructive engagement," he said.

He added that he is confident that if there is a deal on the current phase of negotiations, Ireland will implement it properly.

Such a global deal could be achieved next year, and is "within our reach," he said during an interview following the PwC/Irish Times Tax Summit..

"Will there be one? I don't know because it depends on the abiilty of countries to work together to come to an agreement, to be able to give up some stuff to others," he said.

"We will reach a deal if everybody is reasonably happy with the outcome to reach the deal."

It is not about infringing on tax sovereignties, he added, but about protecting the tax base in a way that doesn't harm business, which would not increase the cost of compliance but which will ensure profits do not fully escape taxation everywhere.

There is recognition that the current system is not sustainable, he claimed, and that there are too many strains in it that need to be released by a subtle limited reallocation of international tax.

If this happens, then we can all stop talking about international tax, he added.

"Ireland will be fine, Ireland will keep its competitive advantage because you are good at attracting international investment, and not only through the double-Irish but for the stability of your tax system, for the stability of the rate and the tax base, and I think you will keep that competitive advantage."

On the issue of a minimum tax rate, Mr Saint-Amans predicted it will happen, because it can already happen unilaterally

But it would be better to have a global agreement, he said and Pillar 2 of the latest negotiating framework tries to get countries to agree a common set of rules on the issue.