One Nation is attempting to gag donors from ever revealing details of discussions at an invite-only, cocktail-dress fundraiser with the party’s senior leadership team, in a move described as a “worrying precedent” for democracy.

Invitations to the “very special evening” at an undisclosed central Sydney venue next Thursday show donors will be charged $3,000 for a “private and very discrete” four-hour event.

Donors have been told they will be meeting with Pauline Hanson; One Nation’s national director, James Ashby; federal MP Barnaby Joyce; the federal party’s chief of staff, Chris Taylor; and its New South Wales leader, Mike Newman.

But unlike at other One Nation fundraisers – including a $2,000 invite-only event in Melbourne in September – this time donors have been asked to abide by a “non-disclosure agreement” preventing them from disclosing the identities of any attendees.…