Public servants in Canberra have been told to bring their own tea and coffee to work as the Abbott government's cut continue to bite.

As agency budgets dry up, thirsty bureaucrats at the Industry Department have been told that tea and coffee for office kitchenettes will not be supplied at departmental expense.

But coffee beans for the taxpayer-funded coffee machines that proved so controversial under the previous Labor government can still go on the company credit card.

Bosses at Industry have also been warned not to bill taxpayers for boozy senior executive service get-togethers and permission for high flyers to bring along their husbands or wives must come from the top, the rules say.

The latest instructions from Industry's finance unit lays down the law on what can and cannot be bought with departmental funds.

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Flowers for the office and alcohol, in most circumstances, are on the banned list.

A departmental spokesman said the orders went out in early August so that public servants drafted in from other departments in "machinery of government" changes would have no doubt about the spending rules.

A cup of tea or coffee for a departmental staffer is not considered "business catering" at Industry.

"The following examples are not considered appropriate, and would be a personal expense: coffee, tea and sugar supplies purchased for use by departmental officials (e.g. for the department's conference/meeting/training rooms or kitchenettes)" the instructions say.

"This excludes the provision of milk."

But coffee beans for department-issued coffee machines for use by departmental officials are considered "business catering" and will be paid for out of official funds.

Cups of tea for volunteers who work for free at the national science exhibition centre Questacon are also safe from the bean counters, the guidance makes clear.

But coffee and tea at team meetings at cafes also make the banned list, along with gifts for public servants moving on or retiring from the department and pot plants or flowers for the office come under the heading "personal decorations" and are not to be billed to the taxpayer.

The department's elite SES are not above the rules, the instructions make clear, and alcohol served at their forums, networking events and other functions are not to put on the departmental credit card.

The 16-page guidance note from the finance unit contains some strong advice for public servants on their duties when accepting or offering hospitality.

"The provision and/or acceptance of hospitality requires careful judgment, due to the possible perception of undue benefit or conflict of interest which in turn can have a significant effect on the reputation of the integrity and impartiality of the department, the Australian Public Service and/or the Commonwealth," the note says.

"Employees must exercise due care and diligence when providing or accepting hospitality."

An Industry Department spokesman said the new guidance was produced so everyone in the department, including new recruits, knew the rules.

"The department has reviewed its policy following multiple machinery-of-government changes over the last few years," he said.

"The guidance is provided to staff to ensure a consistent approach is adopted across the department."