The drugs were seized on Saturday evening.
The Mayo Divisional Drugs Unit searched two houses in the townland of Killasser, Swinford, Co. Mayo yesterday evening at approximately 6 p.m. on January 5.
As a result of this search, cocaine plants at different stages of growth (subject to analysis) was seized with an estimated street value of over €300,000.
Three men - aged 44, 27 and 23 years - were arrested at the scene in connection with this investigation and are currently detained at Ballina Garda Station under the provisions of Section 2- Criminal Justice (Drug Trafficking) Act, 1996.
Investigations are continuing.