A Palestinian sniper shot and wounded an Israeli civilian on Tuesday as he repaired the border fence between Israel and the Gaza Strip, the army said.

The military said in a statement that the Israeli maintenance worker was flown to a hospital in Israel, while security sources said the man had suffered serious wounds.

Witnesses in Gaza said Palestinian militants fired mortar rounds at Israeli military vehicles east of the security fence near Nahal Oz, and reported seeing an ambulance evacuate one person.

Prime Minister Benjamin Netanyahu warned Israel would respond "forcefully" to the attack.

"This is a very severe incident and we will not sit idly by," he said in remarks relayed by his office. "Our policy has always been foiling attacks and responding forcefully to them. We'll do so in this case as well."

It was the latest violence along the border fence, where several incidents were reported in recent days.

On Monday, the army said troops had fired at an individual "trying to place a bomb" near the fence in northern Gaza.

And earlier that day, Israeli police reported a rocket fired from the Hamas-ruled coastal enclave had hit southern Israel without causing any casualties or damage.

A Palestinian was shot and wounded by Israeli soldiers on Friday in southern Gaza, a day after another Palestinian was killed and four wounded along the heavily-fortified fence.

The Gaza-based Palestinian Centre for Human Rights said the man killed on Friday had been collecting scrap in the wasteland near the border.

But the army said it opened fire in response to Palestinian violence, including attempts to place bombs near the security fence.