The editorial piece does not appear in the Irish version of the tabloid
There has been criticism of the UK version of The Sun newspaper, which has used choice phrases to criticise Taoiseach Leo Varadkar.
In an editorial, the paper uses the headline: "Ireland's naive young prime minister should shut his gob on Brexit and grow up".
It then offers "some advice", suggesting Mr Varadkar "needs to accept" that Britain is leaving the European Union.
It says: "His priority should not be picking holes in our position.
"It should be helping make Brexit work for millions of his citizens and ours, including by engaging constructively on a border solution.
"He is too busy disrespecting 17.4 million voters of a country whose billions stopped Ireland going bust as recently as 2010", the piece adds.
It also claims that Mr Varadkar's "rookie diplomacy, puerile insults and threats to veto trade negotiations" are moving a 'hard Brexit' closer.
The Taoiseach held a meeting with British Prime Minister Theresa May on Friday, calling for written assurances before the next phase of Brexit talks begin.
Labour Party leader Brendan Howlin has described the editorial as 'ignorant, bullying and ageist'.
Deputy Howlin said: "The UK Sun is entitled to put its point of view. But the tone of this editorial is deliberately offensive and will contribute nothing to resolving the issues our countries face.
"It reverts to the bad old days when the UK thought it could tell Ireland what to do, a view no longer held by the vast majority of the British people.
"This is an example of what those who support the European Union have been facing in the UK for decades.
"The Taoiseach is representing the interests of Irish citizens and indeed many UK citizens living in Northern Ireland.
"He is not just entitled to do so, he is obliged to do so. And while he continues to do so he will have the support of all the Irish people."
The editorial does not appear in the Irish version of The Sun.