Ireland Prime Minister Leo Varadkar said that he did not want to see an economic border between his country and any part of a post-Brexit Britain.

Varadkar used his speech at Queen's University in Belfast on Friday to call for unique solutions to preserve the relationship between Britain and the European Union (EU) after Brexit, Xinhua news agency reported.

Describing Brexit as the challenge of this generation, Varadkar said every single aspect of life in Northern Ireland could be affected by Britain's departure from the EU.

He warned that time is running out to try to achieve the best outcome for the island of Ireland after Britain leaves the EU.

The Irish Republic, which joined the EU on the same day as Britain more than 40 years ago, is destined to share the only EU border with Britain.

In what was his first official visit to Belfast since becoming the Taoiseach (prime minister), Varadkar said: "It will come as no surprise to anyone here that I do not want there to be an economic border on our island, nor do I want one between Ireland and Britain."

He said supporters of a hard Brexit had already had 14 months to come up with a plan, adding: "If they cannot, and I believe they cannot (come up with a plan) we can then talk meaningfully about solutions that might work for all of us."

Varadkar also commented on the lack of input into the Brexit debate from Northern Ireland as a result of the collapse of the devolved power-sharing executive which has led to the Northern Ireland Assembly being put on hold since March.

Varadkar said the EU 27 (the remaining member states of the EU) would meet in October to decide whether enough progress had been made in the initial phase of negotiations, focusing on the financial settlement, citizens' rights and the Irish border, to enable talks to proceed to the next phase.

He said there was a need for Northern Ireland's voice to be heard ahead of the crunch meeting in the fall. "Today we need an answer to the question, of who do we — and others in Europe — talk to in Belfast? Who will speak for Northern Ireland and her 1.8 million people?"

His own possible solutions for the future relationship between London and Brussels were an EU-Britain customs union if Britain wanted to remain in the customs union, or a deep free trade agreement with the EU if Britain did not want to stay in the European single market.

He said if those arrangements cannot be agreed now there could perhaps be a period of transition during which Britain would stay in the single market and customs union while the issues are worked out.

Varadkar promised that the Irish government would do all it could in Brexit negotiations to achieve the best outcome for peace, freedom, rights and prosperity in Ireland.