The Fianna Fail leader Micheál Martin TD is accusing the government of lacking "urgency and ambition" in its response to Brexit.
He's called for the creation of an "urgent national plan" to reduce the impact of a hard Brexit - and to open up new markets.
In a speech at the Seán Moylan Commemoration in County Cork this afternoon, Micheal Martin said the British government's current policy was "a shambles".
The Fianna Fáil leader claimed Brexit is already undermining Irish businesses and communities.
Mr Martin called for an EU funded programme to help businesses, like the agri-food sector, which are hardest hit by Brexit.
Mr Martin also said this is a challenging moment in our history - he said we need to work to address the fact that the country has become more divided and more unfair than ever after emerging from a deep recession, on top the rising threats from an international situation which could cause deep, long-term damage.