If the public were able to request information of the group, it also had the potential to create "substantial ongoing costs" for the group, as any expense associated with providing information could not be recouped.
Taxpayers' Union executive director Jordan Williams said apparently ratepayers did not count in the organisation's accountability framework, and queried what Mr Yule was hiding.
"If Mr Yule spends ratepayer money on the council credit card he's accountable, but he's saying when he puts the tab on the LGNZ card, which ratepayers also pay for, it's as if it's his own money."
"No other mayor in the country could get away with this. Mr Yule is taking advantage of an old loophole which applies to LGNZ spending so as to avoid the transparency every other mayor in New Zealand is obliged to accept."
Mr Yule refuted Mr Williams claims, including using any loophole and that LGNZ had refused to release the information.
He said he was happy to release his expenses, however as LGNZ was not covered by the Local Government Official Information and Meetings Act, policy would need to be set in order for information to be released.
"I'm very accountable to Hastings, and I'm happy to be accountable to New Zealand," he said.
He and Mr Alexander said this matter would be discussed at their next meeting next month, and that management would seek the national council's views on the issue of releasing information at this meeting.
Although Mr Alexander denied the group was "100 per cent funded" from ratepayers, he said a major source of their revenue was through their membership subscription .
"Councils probably source that from ratepayers but its indirect," he said. "LGNZ the entity does not have a direct line to ratepayers."
Mr Yule noted the group was accountable to its members, who were in turn accountable to residents across the country.
Mr Williams said "this sort of secrecy and obfuscation" was unusual in local government, and would not be expected from someone who was supposed to lead the sector, and wanted to be an MP.
"With it so well known around Hawke's Bay that Mr Yule is seeking the National Party nomination for the Tukituki seat, which will be left vacant by Craig Foss later in the year, the obvious question is what is Mr Yule hiding?" he said.
"Mr Yule should do the right thing and provide the public with transparency."
Mr Yule said he had not decided if he would seek the nomination, and did not "think what [Mr Williams'] asking has got anything to do with that process".
All LGNZ expenses are submitted monthly and must be signed off by the chief executive and the president, in respect of the CEO.
Mr Yule said his budgets were submitted to each annual meeting. They were not specifically included in the annual report.