The head of Upper Egypt's antiquities says to news agency AFP there are very few such reliefs that show both the gods Amun-Ra and Thoth.
Amun-Ra is one of the incarnations of the ancient Egyptian sun god Ra, and Thoth is the god of knowledge, shown with the head of a curved-beaked ibis bird.
The Lund University team is working near Aswan, 850 km from Cairo. The relief was found in an ancient stone quarry, which provided the building blocks of the Karnak and Luxor temples.
The Swedish team has also found a sphinx-shaped statue and a relief that may date from the reign of Queen Hatshepsut, who is thought to have reigned in the period between 1479 and 1458 BC.
Many traces of her reign were destroyed by a later pharaoh, with her images in stone being broken. The relief is described by AFP as showing two obelisks being transported.