The Southern section of the Communist Party of Ireland had suspended its activities from 1941 onwards because of police interference in its activities and the difficulties imposed by the emigration of many members to find work in England. Members were encouraged instead to join the Labour Party (though they were subsequently expelled). The influx of communists (both from Jim Larkins party and the Communist Party of Ireland) to the Labour party and union movement cause a split in Labour with the formation of National Labour. During the time the communists still ran a revolutionary book shop New Books and produced a publication Irish Review.
After the Second World War, internees released from the Curragh Camp such as the Connolly Group and with expulsions from the Labour Party, the party was re-established in the South in 1948 under the name Irish Workers' League. Michael O'Riordan became its Secretary, others involved in early meetings of the party included Dominic Behan, Sam Nolan, Joe O'Connor and Sean Mulready. The IWL resumed publication of The Irish Workers' Voice which had been a publication of the Communist Party. The IWL ran candidates in the unsuccessfully in the 1951, 1954, and 1961 general elections.
In 1962 the name was changed to Irish Workers’ Party, and fielded some candidates unsuccessfully in the 1965 and 1969 general elections. In December 1965 the IWP began publishing a monthly newspaper The Irish Socialist from its New Books bookshop.