The Diocese of Kavieng encompasses the two provinces of Manus and New Ireland. Out of a total population of 96,000 about 45,000 are Catholic. Missionaries of the Sacred Heart (MSC) arrived in New Britain in 1882. By the turn of the century, evangelisation had begun in New Ireland, and ten years later the first missionary priests reached Manus. In both cases, Catechists preceded the missionaries. By 1935 parishes had been founded throughout the two major islands of Manus and New Ireland and on most of the larger adjacent islands.

During World War II/WWII the Vicariate of Rabaul lost over 40 priests and 40 brothers, and most buildings in many parishes were destroyed. After the War came a new influx of missionaries from the German, Irish, and American provinces of the MSC. Schools, churches, convents and health centres were quickly rebuilt from scrap materials salvaged from installations left by the American forces. At the same time, the mission made a strong commitment to education and began training large numbers of local teachers.

In 1957 Kavieng was separated from Rabaul and made a Vicariate under Bishop Alfred Stemper, MSC. In 1966 Kavieng and other Vicariates were made Dioceses, and more conscious attention was given to the development of the local church. The first two national priests from Kavieng Diocese were ordained in 1968.

Bishop Stemper retired in 1981, handing over the Diocese to the care of Bishop Hesse. Bishop Stemper died in Kavieng on 20 February 1984.
Transportation and communication remain the main difficulties due to the size of the Diocese (136kms square).