They were found in burial grounds in the Al-Kamin al-Sahrawi area in Minya province, south of Cairo.
The tombs contained a collection of different sarcophagi, or stone coffins, as well as clay fragments.
Egypt's antiquities ministry said the discovery "suggests that the area was a great cemetery for a long span of time".
One of the tombs, which was reached through a shaft carved in rock, contained four sarcophagi that had been sculpted to depict a human face.
In another, excavators found six burial holes, including one for the burial of a small child.
Clay fragments found at the site date the tombs between the 27th Dynasty, founded in 525BC, and the Greco-Roman era, which lasted between 332BC and the 4th Century.
Ali al-Bakry, head of the mission, said one of the tombs contained bones believed to be the remains of "men, women and children of different ages".
"These tombs were part of a large cemetery for a large city and not a military garrison as some suggest," he said.
In a statement, the antiquities ministry said that "works are under way in order to reveal more secrets".
This work follows previous excavation at the site, which began in 2015.

The two parties have reached a mutually satisfactory agreement and the legal case has been dropped, according to a statement given to Screen Daily.
They producers had claimed her last-minute departure caused delays on the Natalie Portman-starring Western.
The Scottish film-maker had previously denied reports she was being sued.
Ramsay's last film, an adaptation of the novel We Need to Talk About Kevin, starring Tilda Swinton, premiered to critical acclaim in competition in Cannes in 2011.
The film also earned her a Bafta nomination and the best director prize at the British Independent Film Awards.
Jane Got a Gun will tell the story of a woman who asks an ex-lover for help in saving her husband from a gang who want him dead.
Jude Law and Bradley Cooper also left the production shortly after Ramsay. The film will now be directed by Gavin O'Connor, with a cast including Ewan McGregor and Joel Edgerton.
"Jane Got a Gun Production LLC and Lynne Ramsay announce the pending civil action and all other disputes between the parties associated with Jane Got a Gun Motion Picture have been resolved privately and to their mutual satisfaction," said the statement published by Screen Daily.
It was not revealed whether the resolution involved a financial settlement. Ramsay herself has yet to comment.
Several sources claimed the disagreements involved delays and control of the film's final cut, with the Hollywood Reporter claiming Ramsay had not been presented with an approved schedule, script or budget days before shooting was set to begin.
In November, the Hollywood Reporter also published court papers, in which it was claimed Ramsay "was repeatedly under the influence of alcohol, was abusive to members of the cast and crew and was generally disruptive".
Ramsay later issued a statement saying she had not been served with that particular lawsuit.
"The allegations as recently reported are simply false," the statement added. "Lynne looks forward to presenting the truth about this situation in the proper forum."

The UK oil giant has said that fraud and false compensation payments are behind the escalating costs it faces.
But Judge Carl Barbier ruled that there was no "credible evidence of fraud" or that the compensation process was tainted by conflicts of interest.
BP said it continued to believe that the compensation system was being abused.
Former FBI director Louis Freeh is investigating allegations of misconduct in the claims program.
The oil company insists that the payouts should be suspended while Mr Freeh carries out his probe.
In an emailed statement to Bloomberg on Wednesday, BP said: "As we await the completion of this broad investigation [by Mr Freeh], we continue to believe a temporary pause in payments is warranted.
"BP is reviewing its options with respect to the district court's decision today."
The Deepwater Horizon oil rig explosion killed 11 workers and released an estimated four million barrels of oil into the Gulf of Mexico.
BP set up a compensation fund, initially estimating the cost of the settlement at $7.8bn (£5.03bn). The company has since raised the estimate to $9.6bn.
Archaeologists have discovered three tombs that date back around 2,000 years in southern Egypt.
[NEXT_CONCEPT]
Director Lynne Ramsay has settled a legal dispute with the producers of the film Jane Got a Gun, which she quit days before shooting began last year.
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BP has lost a second attempt to suspend compensation payments over the 2010 Gulf of Mexico oil rig disaster.