A union is crying foul over what it claims is a violent attack on its national director during a protest in international waters.

Unite Union's national director Mike Treen was heading to Gaza when he was dragged off his boat by the Israeli military and is being held in prison.

The Freedom Flotilla he was part of aimed to draw attention to what it says is Israel's illegal and inhumane ten-year blockade of Gaza.

Gerard Hehir told Mike Hosking they've written to our Honorary Consul in Israel to get answers from officials.

"Well it was out there on international waters on a boat trying to deliver medical supplies, so it was a hijacking"

LISTEN ABOVE AS GERARD HEIR SPEAKS TO MIKE HOSKING