The church of Hagios Nicholaos is a domed three-aisled basilica. Two main construction phases can be identified: the initial building, dated to the 9^th century, was a three-aisled barrel-vaulted basilica with a narthex on the west side, in the core of which was probably incorporated a ruined Roman edifice. The second phase is dated to 1337/38, according to the donor inscription in the central aisle, and includes the reconstruction of the vaults with the addition of the dome, sponsored by Constantinos Spanes, military governor (tzaousios of the drongos of Melingoi).

The wall paintings are of exceptional artistic value. In the central aisle, dated to 1337/38, especially significant are the imposing figure of the enthroned Christ from the Deesis on the apse, the Pantocrator surrounded by angelic hosts and figures of Prophets on the dome, and the impressive Christological scenes on the vaults and the upper zones of the walls. Their highly artistic quality and expressionistic manner indicate a workshop coming from a significant art centre, possibly from Mystras. The life of Saint Nicholas is depicted in the south aisle, while the painted decoration of the north aisle indicates that it was probably dedicated to the Virgin. The wall paintings of the side aisles are dated around the mid-14^th century, according to the donor inscriptions and their stylistic features.

The project “Consolidation and Conservation of Wall-Paintings and Sculpted Decoration in the Holy Church of Hagios Nicholaos at Kampinari, Platsa” was carried out under the direct supervision of the Ephorate of Antiquities of Messinia, with a budget of  330.000€, during the period from 1-1-2011 to 31-12-2014.  The project included the consolidation of the wall paintings and the sculpted decoration, the conservation – restoration of the dome and partly of the masonry and the installation of new doors.