World Rugby has upped the ante in an attempt to secure agreement for its controversial Nations Championship proposal by increasing the original offer of £5 billion to the competing countries over the next 12 years.

It is understood that an increased offer was made during discussions at the World Rugby council meeting in Dublin on Wednesday.

Significantly, tweaks to the tournament to exclude Japan and Fiji from the original 12-team global tournament were also rejected, given the likely opposition from the World Rugby council.

It is understood that World Rugby hopes the latest cash offer will prove attractive enough, given the tough economic challenges facing countries in the northern and southern hemispheres, to get the deal over the line.

The Six Nations members are also considering a lucrative offer to aggregate their broadcasting rights, which includes an offer of £500 million from CVC, the private equity firm, for a 30 per cent investment, while International Management Group, one of the world’s leading sports agencies, has made a £1.75 billion investment proposal.

It is unclear whether the increased offer from In-front Media, the backers of World Rugby’s proposal, will be enough to convince the sceptics within the Six Nations. The Rugby Football Union was thought to remain “open-minded” about the plan.

Discussions will continue and if progress can be made, a World Rugby council meeting will be convened at short notice next month to vote on whether it will be approved.