Revelations that Treasurer Joe Hockey has met with business people at his parliamentary office in return for big donations to the Liberal Party has triggered a strong rebuke from former Prime Minister Malcolm Fraser, who labelled the practice “corrupt”.

Commenting on reports in the Sydney Morning Herald, which said that the Treasurer used his Canberra office to hold meetings which attracted donations, Mr Fraser tweeted that it “used not to happen” and that “cash for chat is corrupting our democratic integrity”.

Treasurer for sale: Joe Hockey offers privileged access. Used not to happen, practice corrupt http://t.co/RjEB6AVHRc

— Malcolm Fraser (@MalcolmFraser12) May 4, 2014

Cash for a chat is corrupting our democratic integrity. Yes http://t.co/EArKBUYTGW

— Malcolm Fraser (@MalcolmFraser12) May 4, 2014

The secretive fund-raising body activities for the LNP are not fully disclosed to election funding authorities, according to the story in today’s reports.

While this is not a new way of raising funds for political parties, Mr Hockey’s offer enables the country’s richest access to the highest political office.

The donors are members of the North Sydney Forum, a campaign fundraising body run by Mr Hockey’s North Sydney Federal Electoral Conference (FEC) – according to Fairfax.

In return for annual fees of up to $22,000, members are rewarded with “VIP” meetings with Mr Hockey, often in private boardrooms the report says.

Officials for FEC say its membership lists and therefore the identities of its donors are “confidential”.

Mr Hockey also says details of who he is meeting and what is discussed are confidential.

Limited information available to the public reveals members of the forum include the National Australia Bank as well as the influential Financial Services Council, whose chief executive is former NSW Liberal leader John Brogden, say Fairfax.

The North Sydney Forum was established in May 2009, by Joseph Carrozzi, who is the managing partner at professional services firm, PriceWaterhouseCoopers.

Mr Carrozzi is also the chairman of the Italian Chamber of Commerce and Industry in Australia.

He said he had known Mr Hockey for 20 years and was “honoured to be asked,” to establish the forum shortly after Hockey was elected. He says the forum was “essentially there to provide a network and insight for small businesses”.

“Members get an opportunity to sit down and chat with Joe. We’ve had other ministers, state and federal, participate as well.”

Mr Carrozzi also said that Mr Hockey “sits down regularly” with members of the forum, however, he said that the federal treasurer “was certainly not a regular attendee”.

The North Sydney Forum membership structure offers “full membership” for an annual fee of $5500 for which members are entitled to five boardroom events.

The fee for corporate and business members is $11,000 with extras such as “VIP boardroom function” however, for $22,000 private patrons can enjoy an additional 10 boardroom events.

According to Fairfax, in its disclosures, the NSW division of the Liberal Party declares membership fees – regarded as donations for the purposes of the election-funding act – but does not state they are for the North Shore Forum.

This practice masks who is donating directly to the North Shore Sydney Forum and the identity of its members.

A spokesman for the NSW Election Funding Authority said: “There is no record of the NSF in the EFA system.”

The revelations come at a time when the Independent Commission Against Corruption (ICAC) is probing Liberal fund-raising bodies such as the Millennium Forum and questioning their influence on political favours in NSW.

Already ICAC has claimed two high profile scalps with police minister Mike Gallacher resigning on Friday and the Premier Barry O’Farrell resigning in April.