Between 1974 and 1981 Allen made 28 senior appearances for Ireland, making his debut against Wales in 1969. He also represented Ireland at under-23 level. He made his senior international debut against Wales in 1974. He subsequently represented Ireland at the 1978 Men's Hockey World Cup. Allen retired after the 1981 Men's Intercontinental Cup tournament. However he continued to play for the Ireland indoor field hockey team, making 60 appearances. His Ireland team mates included Jimmy Kirkwood.