The debris was found on Tuesday evening on a beach in Karwia on the country's Baltic coast.
A passerby alerted authorities at about 6:30 p.m. after finding an object partly covered with sand and resembling a drone, according to local police.
Military police and prosecutors secured the site and took the wreckage for examination.
Military police spokesman Lt. Col. Dariusz Rozkosz said on Wednesday that chemical, radiological and explosive hazards had been ruled out, while testing for biological materials was continuing.
Kosiniak-Kamysz said the object was the remains of a Polish drone shot down during exercises involving Polish drones and anti-drone systems at a military training area near the coastal town of Ustka several weeks ago.
"This is not some kind of Russian provocation, but the result of exercises at the Ustka training ground," Kosiniak-Kamysz said during a visit to a military unit in Nowy Glinnik, central Poland.
He said the exercises involved the Warsaw-based Air Force Institute of Technology (ITWL), which is working to develop drone and anti-drone systems.
He praised the soldiers and engineers involved and stressed the importance of unmanned systems and technologies for countering drones to Poland's armed forces and national security.
Private broadcaster RMF FM reported that the object was about 2 metres long and was the first to report that the fragments were from a Polish test drone used in military exercises.
The discovery came about a month after another drone washed ashore farther west on Poland's Baltic coast.
In mid-September, a drone found on a beach at Rusinowo, near the seaside resort of Jarosławiec, was identified as a Russian Gerbera-2 drone carrying a warhead with a detonator.
Kosiniak-Kamysz said at the time that it had most likely been lost by Russia during tests over the Baltic Sea. The case remains under investigation by prosecutors and other authorities, Polish state news agency PAP reported.
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Source: IAR/PAP