Opening one of the ornately decorated sarcophagi before assembled media, the team revealed mummified remains wrapped in burial cloth that bore hieroglyphic inscriptions in bright colours.
The dramatic find was unearthed south of Cairo in the sprawling burial ground of Saqqara, the necropolis of the ancient Egyptian capital of Memphis, a Unesco World Heritage site.
"We are very happy about this discovery," said Mostafa Waziri, secretary general of the Supreme Council of Antiquities.
Since the find of the first 13 coffins was announced almost three weeks ago, more have been discovered in shafts at depths of up to 12 metres (40 feet).
An unknown number of additional coffins may still lie buried there, the tourism and antiquities minister, Khaled al-Anani, said at the site, near the 4,700-year-old pyramid of Djoser.
"So today is not the end of the discovery, I consider it the beginning of the big discovery," he said.
People sit near sarcophagus on display after they were discovered at Saqqara Necropolis, Giza, Egypt, 03 October 2020. An Egyptian archaeological mission uncovered a total of 59 intact and sealed coffins in three burial shafts dozen of meters deep in the Saqqara necropolis. The 2500 years old coffins, believed to be belonging to the 26th Dynasty Priests, are expected to be transferred to the Grand Egyptian Museum
The coffins, sealed more than 2,500 years ago, date back to the Late Period of ancient Egypt, from about the sixth or seventh century BC, the minister added.
Excavations in Saqqara have in recent years unearthed troves of artefacts as well as mummified snakes, birds, scarab beetles and other animals.
The discovery of the coffins is the first major announcement since the outbreak of Covid-19 in Egypt, which led to the closure of museums and archaeological sites for around three months from late March.
Anani said all the coffins will be taken to the soon-to-be-opened Grand Egyptian Museum (GEM) at the Giza plateau.
Egypt hopes a flurry of archaeological finds in recent years and the GEM will boost its vital tourism sector, which has suffered multiple shocks since the 2011 Arab Spring uprisings, most recently the pandemic.