The Government has not investigated whether claims that asylum seekers entering Ireland from the UK are true, despite flagging them as evidence of the deterrent effect of the Rwanda plan.

Last week, Ireland’s Justice Minister Helen McEntee claimed 80% of asylum seekers are coming into the country from Northern Ireland, a figure that on Tuesday she said she would “absolutely stand over”.

The statistic has since been questioned by human rights and refugee organisations as well as Irish ministers.

During Foreign Office questions, deputy foreign secretary Andrew Mitchell said the increase in irregular migration in Ireland suggested the Rwanda effect was “having the deterrent effect we are seeking”.

Has the minister been able to establish the veracity or otherwise of such an exceptionally high figure that she has claimed as the case?

Conservative MP Chris Clarkson (Heywood and Middleton) told the Commons: “Recently, the Irish Tanaiste stated that he believed the increase in irregular migration to the Republic of Ireland was a direct result of the deterrent effect of our Rwanda policy.

“The Irish Government has since made moves to try and remove those illegal migrants back to the UK.”

Mr Mitchell replied: “(Mr Clarkson) makes a very good point, what is sauce for the goose is also sauce for the gander.

“The movement of asylum seekers from the UK to the southern Irish Republic would indeed suggest that the Rwanda agreement is already having the deterrent effect we are seeking.”

Later in the session Mr Mitchell said whether the claim that 80% of asylum seekers in Ireland have crossed from Northern Ireland was accurate was a matter for the Irish Government.

DUP MP Gregory Campbell (East Londonderry) told the Commons: “The Irish Republic government and the Justice Minister there indicated that she believes that up to 80% or more of those who are illegally in the Republic of Ireland are coming across the land border, but that appears to have been a purely subjective figure.

“Has the minister been able to establish the veracity or otherwise of such an exceptionally high figure that she has claimed as the case?”

Deputy foreign secretary Andrew Mitchell replied: “We haven’t for reasons that (Mr Campbell) will understand, this as a southern Irish government responsibility, but no doubt the southern Irish government will be being pressed on this matter and in due course will deliver an answer.”

Mr Mitchell went on to deny claims the Government was not willing to come to an agreement with Ireland or the EU on the return of asylum seekers.

SNP MP Patrick Grady (Glasgow North) said: “On one hand, (Mr Mitchell) wants to improve international co-operation on tackling illegal migration and then on the other hand says that they’re not willing to come to an agreement with the government of Ireland or any other European countries on returns of asylum seekers.”

Mr Mitchell replied: “I didn’t say anything of the sort. We are working together in numerous international fora for tackling this matter upstream.”