The Coalition's attempt to have the Productivity Commission examine the Government's $43 billion National Broadband Network (NBN) has failed, with its bill voted down in the House of Representatives.

Opposition communications spokesman Malcolm Turnbull had introduced a private members bill to refer the NBN to the commission, arguing it needed more scrutiny.

But he was unable to secure the votes of enough independents to pass the legislation and it went down by one vote.

Independent MP Rob Oakeshott supported the bill, but Andrew Wilkie, Tony Windsor and Bob Katter sided with Labor as did Greens MP Adam Bandt.

However the Coalition has succeeded in passing another motion in the Senate to urge the Government to produce more documents about the network.

The failure of the bill to pass comes amid a growing row over the NBN as the Government refuses to bow to pressure to release the business plan for the network.

Legislation to structurally separate Telstra is now before the Senate and must be passed to enable the NBN to proceed.

But the Senate wants the Government to release the business case for the NBN before Parliament rises for the summer break next week.

And it is trying to stop any more debate on NBN bills in the Senate until the plan is released.

However, the Government has dug its heels in and will not be making the business plan public until sometime in December.

Senator Stephen Conroy has told AM it would be illegal to release some of the information because of commercial in confidence matters.

And he says Cabinet is yet to consider it.

"Well, it's a 400-page document. We only received it last week. We're in the process of getting a range of briefings," he said.

"We'd like to brief the Cabinet and we don't think that's being unreasonable."

Senator Conroy has offered the Greens a briefing, but Greens Senator Scott Ludlam says they are not happy about being asked to keep it confidential.

Mr Turnbull says the Government is asking MPs to vote on crucial NBN bills without proper details.

"How can we, any of us, Coalition, Labor, crossbenchers, any of us, discharge our duty to the Australian people by approving such a massive project without any financial information about it?" he said.