A fired-up Mr Shorten promised to stand on his record in the union movement during a meeting of Labor's highest administrative body, the national executive, which met in Canberra on Friday.

According to multiple accounts of the meeting, Mr Shorten told the 21-member body that the Prime Minister hoped to use the royal commission into trade unions, which the opposition leader will appear before on July 8, as a platform to demonstrate why Mr Shorten was not fit to be prime minister.

But the Labor leader vowed to turn the attack back on to Mr Abbott and the Coalition and highlight the prime minister's support for Work Choices in the former Howard government.

Mr Shorten also told the meeting, which comprises some of the most senior MPs, factional power brokers and union leaders in the party, that Labor's focus on fairness had been critical to its lead in the opinion polls for the last 18 months.

He also explained the party's decision to oppose changes to the aged pension this week, which has drawn criticism in some quarters.

One person who attended the meeting said it was clear that "Bill's intention is to use industrial relations to show why he should be prime minister".

"This [royal commission] is all about criminalising trade unionism and Labor politics, the view of the national executive is the government will do or say anything."

A second person in the meeting said Mr Shorten "was putting the executive on notice that we are moving to a new phase and approaching a possible early election".

"It was a call to arms and a reminder of the seriousness of our purpose".

Ahead of the July's national conference of the Labor Party, which will feature difficult debates on asylum seeker policy, recognition of Palestine, reform of the party and free trade, Mr Shorten also stressed the need for unity.

A third person who attended the meeting said the executive was united behind Mr Shorten and there was a broad view he had been unfairly maligned.

Mr Shorten's move to put the party on an election footing comes after a difficult week, which culminated in the royal commission into the trade union movement agreeing to bring forward the opposition leader's first appearance to July 8.

The opposition leader is expected to face a series of questions from the commission about his time as both state and national secretary of the Australian Workers Union, including about a work place deal struck with Thiess John Holland on Melbourne's East Link tollway, another deal struck with Winslow Constructors, and on AWU donations to his campaign for the seat of Maribyrnong.

Labor MPs are closely monitoring developments, with a minority fearing the opposition leader could be badly damaged by the royal commission, though a majority believe it is a political-motivated witch hunt designed to damage Mr Shorten.

Fresh concerns were voiced by some MPs on Friday after Fairfax Media revealed Mr Shorten is poised to hire Ian McNamara - who is nicknamed "Joe Triprotege" after his period working for disgraced former NSW state Labor MP Joe Tripodi - as his new director of strategy.

Some MPs and political operatives raised concerns the appointment would bolster the influence of the NSW Right faction in Mr Shorten's office, highlighting his close links to NSW Labor general secretary Jamie Clements, Mr Tripodi and other figures in the Sussex Street political machine as well as an appearance as a witness before the Independent Commission Against Corruption in September last year.

But the head of Labor's staffing committee, federal MP Gary Gray, issued a strong defence of Mr McNamara on Friday, declaring: "I am aware that Ian has a deep background in public administration, I'm aware he has strong qualifications in economics and I'm also aware of the ICAC reference," he said.

"I don't want to comment on any ICAC matter."

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