Both candidates for the leadership of the ruling Conservative Party, Boris Johnson and Jeremy Hunt, have said they oppose Ireland's proposal for a "backstop" clause in Britain's withdrawal agreement that would ensure regulatory alignment between Northern Ireland and the Republic of Ireland.
Both have warned that Britain would be willing to risk massive economic disruption and leave the European Union without a deal if no alternative is found and both have said even a significant concession from the European Union on the Irish border might be insufficient.
"I am going to have to listen to the prime minister, whenever he is elected, and I’ll have a chance to see if they have any meaningful or workable suggestions," Varadkar told Irish broadcaster RTE ahead of the announcement of the results of the leadership contest next week.
"If they have proposals that genuinely achieve the same outcome, I have to listen to them," he said. "If they don’t, then obviously we can’t depart in any way from the Withdrawal Agreement or the backstop."
Any proposal would need to ensure that Brexit should not lead to the emergence of a hard border, that the rights of citizens in Northern Ireland are fully protected and that north-south cooperation on the economy and Northern Ireland's 1998 Good Friday Agreement peace deal be preserved, he said.
"I am willing to compromise, provided those objectives are achieved," Varadkar said.
"I can see a route [to avoiding a hard border] but I don’t think we can take that for granted and that’s why we are stepping up our preparations for no-deal," he added.
One option, Varadkar said, would be for the backstop to cover just Northern Ireland rather than the whole of the United Kingdom, but he said the Democratic Unionist Party, whose 10 members of parliament prop up the Conservative government, would likely have difficulties with that.