Ms Foster issued the demand as Leo Varadkar attempted to calm unionist fears the Republic is using Brexit as a Trojan horse to create a united Ireland after months of worsening relationships between Dublin and Belfast.
In a new year’s message, Ms Foster said she is growing tired of the repeated delays in agreeing a deal between her party and Sinn Féin to restart the power-sharing coalition.
And in a clear ratcheting up of tensions, she said if no developments occur in the coming weeks she will formally ask the Conservatives — whom the DUP is supporting and has the power to bring down the London government — to appoint direct-rule ministers immediately.
“The people of Northern Ireland deserve a government, and if Sinn Féin persist with their intransigence, then the secretary of state should move to appoint direct-rule ministers in the new year,” said Ms Foster.
The comment came despite the Irish Government repeatedly saying it will not accept the return of direct rule in Northern Ireland.
Meanwhile, the Taoiseach has attempted to calm unionist fears over a united Ireland.
Last autumn, Tánaiste and Foreign Affairs Minister Simon Coveney provoked outrage among the DUP and UUP by telling a Dáil committee he wants to see a united Ireland during his political lifetime.
Speaking to reporters during a Christmas round-table briefing, Mr Varadkar supported Mr Coveney’s comments the Republic has a constitutional right to seek a united Ireland.
However, he said this could only ever be achieved by “consent”, adding he is of the view the former SDLP leader John Hume was right to discuss the issue not in “united Ireland” terms but in those of an “agreed Ireland”.
“In terms of a united Ireland, our constitution is clear on this. Our constitution aspires to there being a united Ireland.
“I share that aspiration, but only on the basis that it is done by consent.
“I very much follow the school of thought of the great John Hume who talked less about a united Ireland and more about an agreed Ireland. And a set of relationships that we can all be happy with. That’s the way it should be.”