New NBN board chair Ziggy Switkowski has been called on to attend a Senate hearing.

NBN board chair Ziggy Switkowski has been called on to attend a Senate hearing. Photo: Luis Ascui

A Labor-dominated Senate committee has ordered National Broadband Network executives to appear before it on Friday after they earlier expressed reluctance to attend.

The Senate Select Committee on the NBN, comprising three Labor Senators and one Green Senator, has issued an order for company personnel to appear before its hearing on Friday.

Those summoned include NBN Co's chairman Ziggy Switkowski, head of strategy and transformation JB Rousselot, chief operating officer Greg Adcock, chief technology officer Gary McLaren and chief financial officer Robin Payne.

In a statement issued on Wednesday, committee chairwoman Kate Lundy said the committee was "disappointed" that the company had been "reluctant" for its personnel to attend the committee.

"It is with regret that we have had to issue this summons, given the public commitment the government has made to openness and transparency in all matters relating to the NBN," Senator Lundy said.

Communications Minister Malcolm Turnbull accused the committee of trying to hinder the company's executive team, which is finalising its strategic review.

He attacked former Communications Minister Stephen Conroy, a member of the committee, for being absent from last week's Senate estimates hearings at which company executives answered questions.

“Stephen Conroy is not interested in transparency. If he were genuinely interested in discussing the state of the project, he would have cut back his holiday in Buenos Aires so that he could attend the Senate's Estimates hearings last Tuesday. Only a week ago, his Labor colleagues had four hours to question the NBN Co team but ran out of questions after three hours," Mr Turnbull said.

“This is an attempt by the Labor Senators to disrupt the preparation of the strategic review. They know that the entire senior executive team of the NBN is flat-out finalising this important piece of work. They know that they are therefore not in a position to discuss its contents. But they want to drag them down to Canberra so that a crucial day is lost in the preparation of this report."

But Labor's communications spokesman Jason Clare said it was "outrageous" that the executives were "not even bothering to turn up to a Senate Committee to explain how they are spending more than $30 billion of taxpayer's money".

"If Malcolm Turnbull is really committed to transparency, he will pick up the phone and tell the old mates he has installed in NBN Co to attend the Senate committee hearings. Then they wouldn't need to be summoned."

Senator Conroy said the committee issued invitations two weeks ago, and moved the appearance date for the executives from Thursday to Friday to avoid a clash with an NBN Co board meeting.

''Malcolm Turnbull is resorting to personal smears and false allegations because he is breaking his promise to make NBN Co more transparent and accountable,'' Senator Conroy said.

''Mr Turnbull is well aware that the decision to summons the NBN executives was made by resolution of the committee, not by an individual Senator.

''If Mr Turnbull was true to his word they would turn up to the committee.''

Last week, Labor Senator Don Farrell told a Senate hearing Senator Conroy was absent because he was attending a meeting of the accountability and transparency review team of the Internet Corporation for Assigned Names and Numbers.

The NBN Co has been contacted for comment.