Islamist group says any informers who hand themselves in to authorities by 11 April will not be interrogated or imprisoned

Hamas has launched a campaign to convince Palestinians who collaborate with Israel to turn themselves in, offering promises of impunity and financial rewards.

The Islamist group claims to have obtained a list of Palestinian informers in Gaza, which it has run since 2007. The territory's interior ministry held a press conference in Gaza City to announce that anyone on this list of collaborators who hands themselves in to the authorities by 11 April will not be interrogated or imprisoned. It also offered a monthly salary to the informer's families.

Muhammed Lafi, an official with the internal security service, told reporters: "This campaign against collaborators isn't purely a security campaign, as it also has a social element. We do not discriminate between them according to their political affiliation, and we will provide them with information to make sure they can make right their mistakes and thus protect resistance fighters."

While this is not the first time Hamas has offered amnesty in return for information from Israeli informers, this is its largest-scale campaign to date.

Shawan Jabarin, executive director of the Palestinian rights group Al-Haq, has condemned Hamas's previous denial of a right to fair trial to suspected informers, but like many observers believes the offer of amnesty is genuine. "I'm sure they are serious," he said. "If they weren't, they would destroy popular trust."

The exact number is impossible to determine, but rights groups estimate there are hundreds of Palestinians who have been coerced or have volunteered to spy for Israel from Gaza. Hamas has issued more than 30 death sentences to suspected spies since it took over the Gaza Strip in 2007.

A 31 year-old man who handed himself over to Hamas in 2010 and revealed himself only by his initials, MS, spoke to the Guardian from Gaza's Ansar prison. He is serving a five-year sentence for spying having confessed to providing Israel with information about Palestinian factions and local political figures. His family refused to provide him with a lawyer and his wife is pressing for a divorce.

He explained the process of his recruitment. He met a man he thought was British while studying in Algeria in the late 1990s. It was only years later, after the two had established a firm friendship, that the friend revealed himself to be an Israeli intelligence officer.

"He said he would help me achieve my goal to work with a UN agency. I agreed to keep working with him until my daughter was born. What I was doing made me sick. I couldn't sleep, I was taking drugs to make me sleep," he said. "The first night I was able to sleep was when I handed myself over."

Publicly, Israel refuses to confirm it uses Palestinian collaborators, but Israeli security analysts say despite their sophisticated surveillance technology, the security forces still rely heavily on human intelligence provided by informers such as MS inside Gaza.

Hillel Frisch, an expert on Palestinian politics at Bar Ilan University, points to the Israeli Air Force's 1,300 surgical strikes on targets during the November conflict, all of which required precise local information.

Hamas has claimed the pinpointed execution of Ahmed al-Jabari, commander of Izz ad-Din al-Qassam by the Israeli Air Force as he drove through a densely populated section of Gaza City was based on information delivered by an informer. Jabari's assassination on 14 November triggered the eight-day conflict in which more than 180 Palestinians and seven Israelis were killed.

"[Hamas] offers amnesty deals to informers periodically but they never seem to resolve the problem," Frisch said. "An Israel intelligence officer once told me that Israeli benefits a great deal from information it gets for free. A large part of the population in Gaza resents Hamas for the situation they are in now and this is something they won't overcome."

While Hamas's recent offer of amnesty may be genuine, MS suggests the local community may not forgive as easily. He has two years left to serve of his sentence but plans to appeal for asylum in the US when he is freed. "Nobody accepts me here, I don't know where to go the day I am free – my brothers and sisters are not interested [in] having me among them. I am a traitor," he said.

© Guardian News and Media 2013