Work on Prime Minister Tony Abbott's official Canberra residence was originally expected to take eight months and be completed by mid-2014, but Finance officials have pushed back the completion date at least three times.

The house will now not be ready until mid-2015 – at the earliest.

Responding to a freedom of information request, the department originally sought $67,825 in administration fees to release information related to the $6.4 million project.

A revised request seeking documents only from the past year that explained the delays attracted a $3759 price tag. Officials said nearly 14 hours would be needed to retrieve the documents as well as 176 hours to decide which could be released to the public.

Despite media reports on the project as far back as 2010, questions in Senate estimates hearings and millions being spent on the works – as well as a luxury Forrest home rented for the prime minister at a cost of $3000 a week – officials decided it was not in the public interest to release the documents, nor to waive costs.

A senior departmental executive, John Owens, acknowledged the documents might contribute in some way to public debate but said the release would not "advance the public interest beyond the information that is already available, as well as information that will be available, as Finance continues to publish information".

Finance was asked last week why so many documents had been created to discuss the delay. Officials provided a response that confirmed only that the documents had been created.

The refurbishment works began in September 2013. Originally expected to cost taxpayers about $3.19 million, the latest estimate is for $6.3 million. Last year's federal budget included unspecified extra funds for the work.

One person with knowledge of the project, who asked not to be named because they were not authorised to speak to the media, confirmed there were delays on site.

In December it was reported the delays were related to the search for heritage bathroom and toilet fittings which meet current safety standards. Non-slip floor  tiles and handrails were reported to be contributing to delays.

When in Canberra, Mr Abbott stays at the Australian Federal Police College in Barton at a cost of $110 per night. In Sydney, Mr Abbott's family lives at Kirribilli House on Sydney Harbour.

In May 2014, staff in Mr Abbott's office blocked the release of information on the project, fearing "negative comments" about the project.

Documents showed bureaucrats were instructed to give purposefully vague responses to requests for information and not to identify the Department of the Prime Minister and Cabinet or Mr Abbott's office as the decision makers.

The refurbishment works include a new slate roof, asbestos removal, new electrical wiring and heating, painting, replacement bathrooms and upgrades to police guardhouses.

Designed by Melbourne architects Oakley and Parkes, Stanley Melbourne Bruce was the first prime minister to live in the colonial revival-style home in Deakin in 1927.

The cost of the historic home has made headlines regularly over the decades.

Mr Bruce faced criticism for his complaints, interior decoration and planned changes shortly after the £28,000 construction was completed.

Kevin Rudd, Julia Gillard and 15 other prime ministers have lived at the 40-room house, originally referred to as the Prime Minister's Cottage.

Mr Bruce's successor, James Scullin, protested the cost of the home and chose to live in a government hostel during his one term. Ben Chifley famously lived at the Hotel Kurrajong while in office and John Howard made Kirribilli his primary residence while prime minister.