Attacks by Jewish settlers on Palestinian farmland and crops increased "dramatically" in June, a report released by the Palestinian Authority has shown.

"Since the beginning of June, the settlers attacks escalated dramatically, especially against the land and the trees. In the first week of June, settlers burnt 350 trees Deir al-Hatab village near Nablus, 20 grape vines in Hebron and uprooted 40 grape vines in Beit Ummar village," said a statement from the government released on Wednesday.

Settlers also burned dozens of acres of farmland and more than 1,000 olive trees, the report said.

"These attacks are part of a campaign to terrorise Palestinian farmers and their families. When settlers destroy trees by burning or bulldozing, they are destroying a family?s means of earning its living," it said.

"Such attacks are so frequent that the Israeli authorities must be able to take action if they choose to. But there is little evidence of settlers being brought to justice.

"They seem to be above Israeli law."

Israeli police spokesman Micky Rosenfeld said he was unaware of any statistics indicating a rise in violence in the West Bank.

"Any reports of violence, whether by settlers or by Palestinians, is investigated and dealt with after an official complaint is received," he said.

Annual figures compiled by Israeli rights group Yesh Din about complaints of settler offences have repeatedly shown that nine out of 10 police investigations fail to lead to a prosecution.