Greece's merchant marine ministry says the 35-meter (115-foot) airship can fly as high as 1,000 meters (3,300 feet) and will be tethered to the ground on the island of Samos, which is close to Turkey's coast.
The island is a major arrival point for migrants who travel by sea in small smuggling boats to reach Europe. A ministry statement issued Monday said the blimp will be equipped with radar and a thermal camera and be able to provide real-time, 24-hour monitoring of the surrounding sea.
Greek authorities say it be used on a four-week trial basis starting Tuesday.
Police in North Macedonia say they have detained and plan to deport back to neighboring Greece 79 migrants found hidden in a truck near the two countries' border.
A police statement says the migrants were discovered by a joint border patrol of officers from North Macedonia and Hungary Sunday on a road near the southern border town of Gevgelija.
The truck driver was arrested and the migrants were transferred to a shelter center in Gevgelija ahead of their deportation.
Monday's police statement provided no details on the migrants' nationalities.
Despite a series of border closures in 2016, thousands of migrants who enter Greece illegally from Turkey continue to trek through the Balkans as they seek to reach Europe's prosperous heartland.