NBN caretaker compliance enforcement decisions rest with Switkowski: Turnbull

National Broadband Network (NBN) company chairman Ziggy Switkowski has received the backing of the man who appointed him, Prime Minister Malcolm Turnbull, as well as Cabinet Secretary Arthur Sinodinos, over a decision to ignore advice from Turnbull's department and breach the caretaker conventions of government departments and businesses during elections.

Switkowski found himself in the middle of a political brawl on Wednesday, after a letter from Secretary of the Department of the Prime Minister and Cabinet (PM&C) Martin Parkinson was released that said PM&C had warned NBN a draft opinion article penned by the chairman contained partisan sections.

Speaking to reporters today, Turnbull backed Switkowski, saying he respected the decision he made.

Turnbull also said that compliance with caretaker conventions rests with departmental heads, and in the case of NBN, that means Switkowski himself.

Parkinson noted in his letter that the conventions do not have legal force, and PM&C cannot enforce compliance.

Meanwhile, Cabinet Secretary Arthur Sinodinos told Sky News yesterday that he did not believe Switkowski had done anything wrong, and had been misinterpreted.

"It's clear Ziggy was aware of the conventions, but the conventions themselves do provide for circumstances like this, where an agency head takes a view that the organisation is being impacted," he said.

"I don't think he did anything wrong, but I think he should have realised he was probably walking into a political minefield."

During the 2010 election campaign, then-Opposition member Paul Fletcher asked the Labor government whether it believed a speech by former NBN Co CEO Mike Quigley during the election contravened the caretaker conventions.

Fletcher said that Quigley's address was "unquestionably partisan" and "in clear breach of the letter, as well as the spirit of the Guidance on Caretaker Provisions document".

Responding to Opposition claims that the Labor-proposed 93 percent fibre-to-the-premises (FttP) NBN was a white elephant, Quigley said the NBN would provide an acceptable return to the government.

"Taxpayers will get their AU$27 billion investment back with interest, and they will get a network they can use for decades," Quigley said. "This is, I believe, a much better option for the Australian public than giving billions of dollars of taxpayer funding to subsidise commercial companies to marginally improve today's broadband networks."

Labor announced earlier this week its intention, if elected, to double the FttP footprint to almost 40 percent of premises, following three years of the NBN building towards the Coalition's so-called multi-technology mix model.