The mass grave, measuring 16 by 4.0 metres (52 feet by 13 feet) was pinpointed using ex-inmates' testimony and is believed to be the final resting place of Dutch Resistance worker Jan Verschure, Dutch television news programme Nieuwsuur reported.
The grave was tracked by Verschure's grandson Paul, who spoke to survivors of the concentration camp where some 70,000 people perished between 1941-45, located in northern Germany's Lower Saxony region.
"One of them gave me a map on which he marked where my grandfather was buried," Verschure told Nieuwsuur.
There are few signs left of the horror camp, torched by British troops shortly after it was liberated on April 15, 1945 to prevent the spread of deadly diseases such as typhus.
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Many of the dead were bulldozed into unmarked mass graves around the camp, with up to 10,000 people believed to have been buried in the area.
Dutch archeologist Ivar Schute, who has done an initial probe said he believed there was indeed a mass grave on the spot.
But Jens-Christian Wagner, director of the Bergen-Belsen memorial said further investigation was not possible.
"We have consulted the Jewish community of Lower Saxony and according to religious laws no digging is allowed."
"That's why there's a decision not to start a dig. In any case, the whole camp has been declared a cemetery," he said.