But taxpayers will see little change from $600,000 when 200 of Asia's tax experts arrive in Sydney next month for a five-star talkfest on the Australian public purse.

Against a backdrop of Treasurer Joe Hockey's budget crisis and the Australian Tax Office's current program to slash 3000 full-time workers, the ATO is laying on a four-day event at which, the opposition claims, no expense has been spared.

According to contract documents lodged with AusTender, the ATO is spending $3000 per delegate to host the conference at Sydney's five-star Shangri-La Hotel overlooking the Harbour Bridge and Sydney Opera House.

Almost $50,000 has been spent to take delegates for a visit to Taronga Zoo which will include a $135-a-head lunch, total bill $27,000.

Tender documents show that a professional photographic service has been hired at a cost of $20,000 – or $100 per attendee – to take pictures at the conference.

A company called Paddywack Promotional Products has been paid $11,000 to provide mementos for delegates. Paddywack's product range includes polo shirts with a choice of logo, stubby holders, fridge magnets, mugs and water bottles, according to its website.

On Saturday, it was reported that Prime Minister Tony Abbott had personally axed $40,000 for promotional showbags for G20 delegates, describing it as "frivolous spending".

But Mr Abbott's office declined to comment on the ATO's spend on corporate goodies that will promote the 44^th Study Group on Asian Tax Administration and Research, which brings together tax experts from 16 Asian and Pacific nations, including China, Indonesia, Japan, Mongolia, New Zealand, Singapore, South Korea, Thailand, Vietnam and the Philippines.

Tax Commissioner Chris Jordan will welcome his equivalents from those countries, as well as senior tax officers.

The ATO defended the price tag for the conference, saying it was the "flagship event on the ATO's international engagement calendar and an opportunity to build relationships and capability in the Asian region".

An ATO spokeswoman said the main topics of the event are base erosion and profit shifting, tax transparency, collaboration and capability development.

"These themes align with G20 and OECD priorities and underpin our efforts to drive collaborative approaches on international taxation matters to ensure jurisdictions get their fair share of taxation," she said.

"We expect the event will lead to improved risk management of large businesses, greater sharing of tax and financial information and opportunities to improve training and capability in our respective organisations."

Opposition Leader Bill Shorten accused Mr Hockey of "showing off to overseas tax bureaucrats at one of Sydney's finest hotels".

"Clearly, the budget emergency doesn't extend to Joe Hockey and the Shangri-La," he said.

"Joe Hockey wants to cuts pensions and introduce a GP tax but is happy to splash out more than half a million to hold a conference and a few meetings at one of Sydney's finest hotels.

"I think most Australians now agree that the Abbott government's priorities are beyond warped. Why should pensioners and Australian families have to do the heavy lifting so Joe Hockey can show off to tax bureaucrats from overseas?"

Australia last hosted the SGATAR event 10 years ago in Sydney.

Despite repeated requests, Mr Hockey's office and Finance Minister Mathias Cormann both declined to respond to detailed questions.