Labor is set to review an internal party tribunal finding that mailing addresses for ballot papers in the 2013 federal leadership vote were altered.

Bill Shorten defeated Anthony Albanese 52 per cent to 48 per cent in an historic party ballot for the Labor leadership involving the federal caucus and grassroots members in October 2013.

But the integrity of the vote has been called into question after a NSW Labor tribunal found changes to the addresses of 50 members had been authorised by party official Kaila Murnain.

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The changes were made at the request of Michael Buckland, who at the time was a senior policy adviser for NSW senator Sam Dastyari.

The mailing addresses of at least 20 Labor members were changed to the home address or post office box of Auburn councillor Hicham Zraika, who was suspended on February 9 from the ALP for six months after branch stacking charges were brought against him.

The tribunal found Mr Zraika should have alerted the party office when he received the 20 ballot papers that were supposed to have gone to other members.

“The arrival of more than 20 ballot papers must have been quite alarming,” the tribunal said in a document revealed by Fairfax last week and confirmed by AAP.

“It required positive action because it was necessary to preserve the integrity of the (federal Labor) leadership ballot.”

Ms Murnain argued the changes were handled by staff in accordance with party rules and it had been a very busy period with many address changes being requested.

The NSW branch’s administrative committee will examine the tribunal finding at its April meeting, after the March 28 NSW state election, AAP has confirmed.

A senior party member told AAP they believed there were “more than 50” alterations made and the issue should be taken to the party’s national executive.

“I hope the party looks to ensure it doesn’t happen again,” the member said.

“The national executive can’t dig their head in the sand.”

NSW ALP secretary Jamie Clements and national secretary George Wright declined to comment.

Comment was being sought from Mr Shorten.

Mr Shorten lost the grassroots ballot, but scored enough caucus vote to get him over the line.

It’s been estimated if Mr Albanese had won just over 1200 more grassroots votes he would have been leader.

Liberal frontbencher Concetta Fierravanti-Wells used parliament last week to challenge Mr Shorten and Senator Dastyari to reveal what they knew of the activity.

– AAP