Gußwerk has belonged to the Mariazell parish since its inception.
When Abbot Eugenius Graf von Inzaghi built the iron foundry in 1745, Gusswerk got its own pastor. The area from Gollrad to Greith was part of Mariazell. Gußwerk received its own church in 1850. The frescoes are by Brother Lukas Reicht, a monk from Seckau.
1958 Gußwerk became its own parish with the branch churches Wegscheid, Gollrad and Greith. The Church of the Holy Cross was built by the owner of the cast iron works.
Today the parish with the branch churches belongs to the parish association Mariazell-Gußwerk (Tel .: 03882 2595)
The church "Zum Heiligen Kreuz" in Gußwerk was built in 1850 on behalf of the former k.k. Montan Ärars built by master builder Zearo from Judenburg and designated by Abbot Joachim Suppan of St. Lambrecht.
The high altar painting by J. Binder is considered an artistic masterpiece. The two Sanctus candlesticks, the communion grille, the latticework of the gallery parapet, the candelabra on the side walls, as well as the baptismal font and holy water basin are art casts of the old, local iron casting, which was closed in 1898 and gave the place its name.
The statue of the Virgin Mary is the work of a Tyrolean master. The ceilings and murals come from the Benedictine brother Lukas Reicht from Seckau. The iron folk altar is a remarkably good work of art. It was designed by master locksmith Fritz Weißenbacher from Gußwerk and executed by the Voest factory school in Linz.
The interior was restored in 1951 and 1952, in 2017 and 2018 the sacristy and parts of the nave were renovated and the church was expanded to include a barrier-free side entrance. Two splinters from the cross of Christ - set in a valuable baroque reliquary - are shown annually at the festival of the Exaltation of the Cross in September.
On October 5, 1958, the parish was raised by Diocesan Bishop Dr. Josef Schoiswohl, the son of a Gußwerker foreman, the previous factory church was elevated to a parish church.
Four branch churches: Wegscheid, Gollrad, Greith and Weichselboden belong to the parish of Gußwerk.