"Finding Tutankhamun's tomb last century was the greatest cultural discovery in Egypt in the history of mankind," Antiquities Minister Mamduh al-Damati told a news conference on Thursday.
"If we find anything today, it will be the most important discovery of the 21st century," he said.
British Egyptologist Nicholas Reeves is in Cairo to probe his theory that legendary beauty Nefertiti is buried in a hidden chamber.
However, Damati believes such a tomb could contain Kiya, a wife of the pharaoh Akhenaten, or his daughter Merytaten.
Both men do agree on one thing -- they hope that sophisticated radar equipment will reveal the existence of another funerary chamber in the heart of Tutankhamun's tomb.
The final resting place of the boy king, who died in 1324 BC after just nine years on the throne, was discovered by another British Egyptologist, Howard Carter, in 1922 in the Valley of the Kings near Luxor in southern Egypt.
Reeves's theory is that Nefertiti is buried in a room adjacent to the tomb of Tutankhamun, Akhenaten's son.
According to Reeves, Tutankhamun, who died unexpectedly, was buried hurriedly in an underground burial chamber probably not intended for him.
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His death would have forced priests to reopen Nefertiti's tomb 10 years after her death because the young pharaoh's own had not yet been built.
Archaeologists have never discovered the mummy of the queen who played a major political and religious role in the 14th century BC.
Nefertiti actively supported her husband Akhenaten, the pharaoh who temporarily converted ancient Egypt to monotheism imposing the single cult of sun god Aton.
Back in Cairo after three days in the Valley of the Kings, Reeves explained his theory that covered lines on the frescoed walls of Tutankhamun's burial chamber, visible only via scanners, show there are two hidden doors.
Reeves, professor of archeology at the University of Arizona, believes one door could conceal the burial place of the tomb's original owner -- Nefertiti.
Visiting the tomb on Monday, Damati said: "I am now 70 percent certain that we are going to find something."
"If another wing to this tomb or one that predates it is found, that alone would be a major discovery," he said.
On Thursday, the minister said a committee of experts had yet to approve further searches, but he hoped to obtain permission to use sophisticated radar to probe the walls in November.
"It shouldn't take very long to discover whether there is an artificial wall there," Reeves told reporters.
"If we use radar and thermal imaging combined, that will give quite fast results. We should know in days if there is a hollow behind the walls."