The taoiseach says the idea, which has been trumpeted by Boris Johnson, should be assessed seriously and should not be dismissed out of hand.
“Prime minister Johnson is genuinely interested in taking a serious look at this idea of building a bridge between Antrim and Scotland,” Mr Varadkar told The Sunday Times. “I know people dismiss it, but I don’t. It needs to be looked at, it needs to be at least examined.
“I’ve seen what the Chinese have got . . . 100km-long bridges. I don’t know if it is viable but I also don’t think it should be dismissed out of hand, and I know he is particularly excited about that one.”
Mr Varadkar also pushed the case for the completion of the A5 in the north-west and a high-speed rail link between Dublin and Belfast.
“The kind of projects that I would really like to see go ahead are projects like the A5 [road], which is being held up because there are no ministers in Northern Ireland,” added Mr Varadkar. “That is really important for west Ulster — Donegal and Derry and border counties such as Monaghan.
“I would love to see a high-speed train link between Dublin and Belfast, cities that are very close to each other but don’t work together enough.”
He also suggested his government could give financial support to at least three big infrastructure projects north of the border and called for zero tariffs on trade between Britain and the EU under any new free trade deal after Brexit.