Rayed Ali, the Saudi student deported from New Zealand on national security grounds, has disappeared after reaching Saudi Arabia.

New Zealand authorities will not say who Rayed Mohammed Abdullah Ali was handed to on arrival in Saudi Arabia but his family have told the Herald they had not heard from him.

His 27-year-old brother, Abdul Mohammed, who lives in the United States, says the family are anxious to know Rayed's whereabouts. He learned of his brother's deportation on the internet, after Herald inquiries last week prompted the Government to admit it expelled Ali on May 30.

Abdul Mohammed said the family knew nothing of Rayed's circumstances. "Someone said he was taken to the Yemeni embassy or consulate in Saudi Arabia but they denied it."

The deportation is only the second under the Immigration Act's national security clause, section 72, which has no right of appeal and requires the Governor-General's signature. The Government says it used section 72 because of Ali's direct association with those responsible for the September 11 attacks on the US; his activities in the US before then and the nature of his activities in New Zealand. While living in Phoenix, Arizona, he was linked to September 11 suicide pilot Hani Hanjour, who flew American Airlines Flight 77 into the Pentagon, killing 189 people. Ali was questioned after September 11 but was not wanted by the FBI.

Ali arrived on a student visa and enrolled in an English course in late February. Authorities began watching him after he approached the Ardmore Flying School in mid-April about completing his commercial pilot's licence.

Intelligence expert Paul Buchanan said few of the 9/11 pilots had sought a commercial licence but it was possible Ali was planning an operation. New Zealand might have got wind of a plot to use planes in the Middle East and "rendered him" to the Saudis. "He may not ever appear again."

On the other hand, there was much to suggest his pursuit of his commercial pilot's licence was completely innocent, Mr Buchanan said.

Herald inquiries this week have uncovered nothing about his activities in New Zealand which posed a national security threat - unless having known a hijacker and flying a Cessna are sufficient grounds.

Abdul Mohammed corroborated Ali's story that he came here to pursue his dream of becoming a commercial pilot. He had passed his private pilot's licence in the US and was doing instrument training before September 11 but after the attacks was unable to fly and returned to Saudi Arabia.

"Rayed felt he had let Dad down by failing to graduate [in the US]," Abdul Mohammed said. "He just decided he wanted to finish [his pilot training]."

He says he spoke to Rayed a few days before he was deported, when he said he was about to renew his visa (which ran out on May 21).

His father had since been trying to contact him on his cellphone "but it is off all the time".

Ali's parents were supporting him financially in New Zealand. His father runs a fabric import-export business in the far northern town of Arar, near the border with Iraq.

Rayed Mohammed Abdullah Ali was born and raised in Mecca but travelled on a Yemeni passport because his father is from there.