A Palestinian farmer was wounded on Wednesday after being shot by Israeli troops near the border in southern Gaza, health officials said.

The 22-year-old man was in a moderate condition after being shot in the stomach as he farmed land near the border in an area east of Khan Yunis, Gaza health ministry spokesman Ashraf al-Qudra said.

The army had no immediate comment.

Israel maintains a security buffer zone along the inside of the border but allows "civilian access on foot to areas up to 100 meters from the perimeter fence, for agricultural purposes only," the UN humanitarian agency (OCHA) says.

In a separate development, five fishermen were arrested by the Israeli navy in waters just off central Gaza, the head of the fishermen's syndicate told AFP.

An army spokeswoman said two fishing vessels had refused repeated calls to turn back to the shore, prompting the navy to escort them to an Israeli port where five men were being questioned.

"Every deviation from the designated fishing zone poses a possible security threat to Israel," she said.

"Since Operation Protective Edge, there have been multiple attempts to smuggle illegal materials and weapons into Gaza from the maritime border," she added, referring to a devastating 50-day Israeli assault on Gaza last summer that claimed the lives of 2,200 Palestinians most are civilians and 73 on the Israeli side most are soldiers.

Under the terms of Israel's nine-year blockade, Gaza's fishermen have the right to trawl the waters up to six nautical miles off the coast, but locals say the Israeli navy often opens fire before they reach that limit.