PARIS: France and Germany pushed for a "historic" agreement among major economies on a minimum tax rate for multinational corporations Wednesday, hoping to shore up support after sceptical European countries expressed opposition to the plan.

Spearheaded by US President Joe Biden, the proposal for a 15 percent minimum tax rate has hit turbulence after Ireland's finance minister expressed "significant reservations" over it.

"The change of (US) administration offers a historic opportunity... and we have to seize opportunities when they present themselves. It's now. It's now that we must act," insisted French Finance Minister Bruno Le Maire at a joint press conference ahead of the upcoming Franco-German Economic and Financial Council.

His German counterpart Olaf Scholz said he was "optimistic" about the chances of sealing an agreement he said would end "disastrous fiscal competition" between countries.

"We are very close to concluding an international agreement" which will lead to "a revolution in international corporate taxation," Scholz added.

Biden's administration last week called for agreement on a unified tax rate of a minimum of 15 percent in negotiations with the Organisation for Economic Cooperation and Development (OECD) and the G20.

But on Tuesday Ireland's Finance Minister Paschal Donohoe said the country had "a really significant concern" about a global rate that meant "only certain countries, and certain size economies can benefit from that base".