Labor has accused Peter Dutton of breaching ministerial rules by failing to pay taxpayers for the value of his mobile office caravan’s refurbishment, gifted to him by a business in north Brisbane.

In May 2017 Dutton declared that Kedron Caravans had refurbished the caravan’s interior, but the Department of the Prime Minister and Cabinet has revealed he is not among those who paid for gifts valued over $300 in 2017.

Under the relevant rules gifts above that value must be purchased by ministers paying the difference to the department.

In an answer to a question on notice, the department revealed that in 2017 only then-prime minister Malcolm Turnbull and senator Concetta Fierravanti-Wells had paid for gifts, which ranged from $55 for a calligraphy print to $1,925 for a silk carpet from the president of Afghanistan.

Labor believes the fact Dutton declared the gift on the parliamentary register of pecuniary interests indicates the caravan renovation is worth more than $300 and should have been paid for by now.

Dutton has used the caravan as a mobile office since 2001, although photos uploaded to social media indicate it has been spruced up, with new signage indicating Dutton has made “over 2,000 visits and counting”.

According to an article in Caravan World that features on the Kedron website, Dutton is a caravan enthusiast who bought his first caravan, a 1974 York, years ago from Kedron.

The article states that in 2016 the MP visited Kedron’s Brendale factory “to congratulate the Gall family on 50 years of industry service and to help launch Kedron’s new suspension kit”.

Kedron Caravans is a manufacturer that offers custom-builds of new caravans but does not appear to offer a refurbishment service.

At Senate estimates on 18 February, officials said the department did not cross-reference the pecuniary interest register with payments made by ministers to check whether they were abiding by their obligations.

Stephanie Foster, the deputy secretary of the governance group, confirmed that if Dutton had made a payment it “should appear” on the 2017 list produced by the department. Foster suggested the department could question the Department of Home Affairs about the value of the caravan renovation.

The shadow attorney general, Mark Dreyfus, labelled the gift a “sweetheart deal” and said Dutton should have paid back “any monies owed that were above the limit of $300”.

“It is clear this gift would be worth more than $300,” he said.

“He is flouting the rules on gifts.”

In October, Julie Bishop faced similar questions over whether her Jimmy Choo shoes were above the $300 limit, but denied breaching ministerial rules.

In February the attorney general, Christian Porter, denied reports that the former state Liberal politician Joe Francis had given three buses to the Liberal party, saying the party had agreed to pay for them but the transaction had not yet been completed.

A spokesperson for the Department of the Prime Minister and Cabinet said Dutton had declared the item on his pecuniary interests register.

“What constitutes an official gift in accordance with the [guidelines] and the declaration of official gifts is a matter for individual ministers.

“Declarations of official gifts that are over the allowable limit are to be declared to the Department of the Prime Minister and Cabinet, in accordance with the guidelines.”

Dutton and the Department of Home Affairs have been contacted for comment.