The call came at 11pm on a Saturday. Yitzchak Ben Mocha's mobile flashed up "unidentified number" but he knew who it was. A recorded voice ordered him to report for duty at eight the next morning. As he packed his uniform he wondered if he was heading to prison. The 25-year-old paratrooper was about to tell his commanders that not only would he refuse to join Israel's war in Gaza but would not serve in any capacity that helped perpetuate the conflict.

He reported for duty and was ordered to erect tents for combat soldiers.

"I told my officer, I am not going to do this. The next morning I was sent home. They told me they'd call me again if there was need. They have not called yet. In the past the army used to put refuseniks in jail for weeks. When they were released, sometimes they would be arrested again and this would go on for months.

"But now it seems the army doesn't want to admit publicly there are refuseniks. [It] is embarrassed. It would go against the image of the whole army and country united behind this war."

The Israeli military has told the press there is so much support for the assault on Gaza that more soldiers have turned up to fight than have been called up for what the local media is characterising as a "righteous war". Ben Mocha says that obscures the increasing number of Israeli men of fighting age, almost all of whom are military reservists, who are refusing to serve the occupation.

One resisters' organisation, Courage to Refuse, published a newspaper advert condemning the killing of hundreds of Palestinian civilians and calling on soldiers to refuse to fight in Gaza. "The brutal, unprecedented violence in Gaza is shocking. The false hope that this kind of violence will bring security to Israelis is all the more dangerous. We cannot stand aside while hundreds of civilians are being butchered by the IDF [Israel Defence Force]," it said.

But it is not clear how many have refused to go to Gaza, because the army is sending people home, quietly. So far, only one reservist has been jailed for refusing to fight. No'em Levna, a first lieutenant in the Israeli army, was sent to a military prison for 14 days. "Killing innocent civilians cannot be justified," he said. "Nothing justifies this kind of killing. It is Israeli arrogance based on logic. It's saying, 'if we hit more, everything will be okay'. But the hatred and anger we are planting in Gaza will rebound on us."

Ben Mocha is hardly a pacifist or anti-Israeli. He grew up in a Jewish orthodox family, attended a religious school, and served full-time in one of Israel's elite combat parachute units.

He says he joined the Israeli army believing he would be fighting "terror organisations". He found himself suppressing Palestinian aspirations for freedom and putting down protests of Palestinian farmers "against the incontinent theft of their lands". He also saw abuses, such as Israeli troops sending Palestinian women and children into houses to ensure they were not booby-trapped, and using civilians as human shields.

"I am not a pacifist. I recognise the necessity of Israel to have a strong defensive army but I'm no longer going to play a part in 40 years of occupation. I told the army I will report for training so that I can always be ready to defend Israel, but attacking Gaza and perpetuating occupation is not defending Israel."

That is not a popular view in a country where worship of the military begins in school and many political leaders are former generals. But the war is likely to strengthen the resisters once Israelis can reflect on the scale of the killing.

In 2003, the army sent Yoni Ben Artzi to prison for 18 months for declaring himself a conscientious objector. Ben Artzi, the nephew of Binyamin Netanyahu, the former prime minister favoured to return to power in the next general election, was called before a "conscience committee", made up just of military officers. It said he was not a pacifist - on the remarkable grounds that his persistent resistance to the army was evidence of the qualities of a soldier.

He spent longer in jail than any other refusenik, but recently the military has preferred to pretend simply that dissenters don't exist - as hundreds of soldiers and reservists signed petitions refusing to enforce the occupation.

The government was particularly embarrassed when 27 pilots said they would no longer carry out killings of Palestinian leaders in Gaza, and when a group of elite commandos refused to serve in the occupied territories.

Still that remains a minority view. "Some of my comrades from the army don't like what I'm thinking. Some said they don't agree but they support my right to say it. But now, with the war, they say I'm giving my unit a bad reputation," said Ben Mocha.

He is disturbed that most of the Israeli public and much of the media is blind to the fact that hundreds of Palestinians have been cut to pieces by Israeli fire power. "In the long run, it's not a war of defence. We are creating a thousand suicide bombers for the future from the brothers of the dead, the sons of the dead ... in the long term, we are creating more terror. You can't separate the war in Gaza from the fact that the Palestinian nation is under occupation for more than 40 years. I'm not justifying Hamas firing rockets but we Israelis should first look at what we are doing."