The government is asking the Federal Court of Appeal to quash an order for the release of documents about four senators at the heart of the 2013 Senate spending scandal.

The appeal filed late last month came on the same day lawyers for the federal transparency watchdog filed their own appeal to more fully reveal details in dozens of pages about Mike Duffy, Pamela Wallin, Patrick Brazeau and Mac Harb.

Both sides believe a Federal Court judge erred in his analysis of how federal officials decided to withhold more than two dozen pages of internal documents and his subsequent decision to release parts of the documents.

Neither side in the case has responded to a request for comment.

It is the latest twist in a two-year-old legal battle between the Prime Minister's Office and the information commissioner stemming from an access to information request The Canadian Press filed in 2013 at the height of the spending scandal.

And it all arrives as the Liberals are facing criticism over legislation to reform the transparency law at the centre of the case.

Sean Holman, an expert on the access to information regime, said the arguments in the case show the divide over the transparency law before Parliament.

"On one side, you have those who believe that decision-making should be private and all aspects of it should be hidden from public view and on the other side you have those who believe at least some of that information about decisions should be in public hands," said Holman, an associate professor of journalism at Calgary's Mount Royal University.

"This is the perennial argument."

In September, a Federal Court judge ordered the Privy Council Office, the central bureaucracy that serves the prime minister and cabinet, to partially release the documents — including a memo Canada's top bureaucrat wrote to then-prime minister Stephen Harper — ruling they were wrongly classified as sensitive legal or ministerial advice and thus exempt from public release under the access law.

Both appeals argue Justice James O'Reilly incorrectly assessed the sensitivity of the information in the documents, erred in his evaluation. (Canadian Press)

Justice James O'Reilly also agreed that portions of the documents related to Duffy, Brazeau, Wallin and Harb should remain out of public view — although those details of the written ruling were among large swaths that remained redacted in order to give the government a chance to appeal.

The government decided to do so on Oct. 13. So too did lawyers for information commissioner Suzanne Legault.

Both appeals argue that O'Reilly incorrectly assessed the sensitivity of the information in the documents and erred in his evaluation of how officials decided to refuse releasing multiple pages.

In August 2013, The Canadian Press filed an access to information request to the Privy Council Office for any records created since March about the four senators.

Officials refused to release 27 of 28 relevant pages, providing only what O'Reilly described as "innocuous information" like letterhead, signatures, dates and names.

The information commissioner took the Prime Minister's Office to court in late 2015, believing officials "erred in fact and in law" when they declared every word on the 27 pages to be exempt from the Access to Information Act.