Only part of the mosaic, measuring 19 metres long and seven metres wide, has been excavated in the southern coastal city of Larnaca and officials believe that more is still buried.
"A preliminary estimation would suggest that scenes of the Labours of Hercules are depicted and that it is dated to the Roman Period," the antiquities department said in a statement.
It said this is evidence that Ancient Kition -- on which modern Larnaca was built -- played an important role in establishing Roman culture in Cyprus.
Cyprus was under the control of the Roman Empire from 31 BC until the 4th century AD.
Transport Minister Marios Demetriades, who visited the site in Larnaca, told reporters that the department of antiquities, which falls under his ministry, planned to move the mosaic to a museum.
Demetriades, who is also minister of works and communications, said the mosaic was important because "nothing similar has been discovered so far".
The eastern Mediterranean island is home to many antiquities and is rife with excavations, involving experts from several countries.
On Tuesday the antiquities department said a French-led team had uncovered near the city of Limassol buildings dating back more than 11,000 years in what is thought to be "the earliest manifestation of an agricultural and village way of life known to date, worldwide.
