Hamas fighters. File - AFP
The Hamas military court said it had issued sentences "against a number of informants, including six death sentences, other sentences varying between life terms and temporary hard labour, and one acquittal."
Hamas takes a rigid approach to collaborators with Israel, which has put the impoverished enclave under blockade since the Islamists took power in 2007.
In 2018 a Hamas military court sentenced six people to death for espionage, including a woman.
The year before, three convicted in the assassination of a Hamas commander were hanged or shot by a firing squad in public.
Hamas said Thursday that collaborators who turn themselves in will face more lenient terms, and said that the "judgments issued have fulfilled all legal procedures."
Palestinian law requires approval from the Palestinian Authority president for the death penalty, but Hamas in Gaza has carried out a number of executions without permission from president Mahmoud Abbas.
Rights groups in Gaza have urged Hamas to reduce its use of the death penalty.
Earlier this month the Gaza-based Al Mezan Center for Human Rights called for a moratorium on the death penalty, saying it was "gravely concerned about the incessant issuance of death sentences by the military judiciary" in the enclave.
In May, Israel carried out devastating 11-day airstrikes on the Gaza Strip, killing 260 Palestinians, injuring hundreds, and destroying tens of residential buildings.
In Israel, rocket fire from the Palestinian territory killed 13 people, including a soldier, according to the police and army.