Ireland plans to return asylum seekers to the UK under new emergency laws, in an effort to stem arrivals through Northern Ireland.

The taoiseach, Simon Harris, has asked the justice minister, Helen McEntee, to bring proposals to cabinet next week to allow the return of inadmissible international protection applicants to the UK, amid concern that Rishi Sunak’s Rwanda plan was rerouting asylum seekers from Britain.

It follows a claim by Sunak that the Conservative party’s deterrence was working, and after it emerged that 80% of recent asylum seekers to Ireland came via the land border with Northern Ireland.

A spokesperson for Harris said he did not comment on the migration policies of other countries but that to protect the integrity of Ireland’s migration system he had asked the justice minister to bring proposals regarding the designation of safe third countries and allowing the return of inadmissible international protection applicants to the UK.

“Ireland has a rules-based system that must always be applied firmly and fairly,” the spokesperson said. “This is one of a number of measures we are taking to strengthen our system and ensure that it is strong, effective and agile. Rules and the integrity of our migration system will be to the fore of our actions.”

McEntee said she would shore up Ireland’s controls and discuss the return of refugees with James Cleverly and other British officials during a visit to London.

“That’s why I’m introducing fast processing, that’s why I’ll have emergency legislation at cabinet this week to make sure that we can effectively return people to the UK and that’s why I’ll be meeting with the home secretary to raise these issues on Monday,” she told RTÉ.

Ireland had previously designated the UK a “safe third country” to which asylum seekers could be returned but last month the Irish high court ruled that this breached EU law, impeding further returns.

In an interview with Sky News on Sunday, Sunak said the Rwanda legislation signed into law last week was already having an impact because people were worried about coming to the UK.

“Illegal migration is a global challenge, which is why you’re seeing multiple countries talk about doing third-country partnerships, looking at novel ways to solve this problem, and I believe will follow where the UK has led.”

Last week, a protest in County Wicklow over proposed refugee accommodation led to violent clashes with police who used shields and sprays and arrested six people. Police said rocks and other missiles were thrown and they recovered an axe.

There have been protests and arson attacks on proposed refugee accommodation centres around Ireland in recent years, fuelling anxiety over far-right agitation and threats against politicians.

In a speech to be delivered later on Sunday the taoiseach said warning signs around the abuse of public figures should be taken seriously. “We know how this story ends,” Harris will say. “We have had too many warnings and we need to take them seriously before the unthinkable happens.”

Ireland has taken in more than 100,000 refugees, about three-quarters from Ukraine. There is an acute housing crisis that has driven up rents and homelessness and fuelled anti-immigrant sentiment. A riot last November wrecked parts of central Dublin.