Parliament is determined to defend its authority to compel witnesses, with a senior counsel engaged to emphasize the legislative body's power in these matters.

The Public Service Association of NSW condemned threats against ministerial and public sector staff, emphasizing that the power of arrest resides with courts, not Parliament, and called for stronger protections against political interference.

The case questions whether the 1901 Evidence Act aligns with modern constitutional principles, particularly the separation of powers, and whether ministerial staff can be legally compelled to testify, with Cullen arguing the law does not account for judicial independence.

The investigation has intensified tensions over parliamentary powers, with the Legislative Council asserting its authority under the Parliamentary Evidence Act to compel witness attendance.

The inquiry involves allegations that the Premier's office leaked privileged information, with the minutes initially considered for referral to ICAC, but only the report was referred, not Minns himself.

In a significant legal showdown, James Cullen has filed a challenge in the NSW Court of Appeal against a summons related to a leak of confidential minutes from a report on the sale of Rosehill racecourse, arguing that the law used to compel him is unconstitutional and threatens judicial independence.

This case centers on the New South Wales Parliament's contentious power to enforce subpoenas and compel witnesses, with Cullen's refusal to appear prompting threats of arrest and a legal battle over parliamentary privileges.

The dispute raises fundamental questions about the scope of parliamentary powers, the immunity of ministerial staff, and whether legislative reforms are needed to clarify these issues in the context of modern governance.

A similar legal dispute occurred earlier in June involving Minns' staff over a different inquiry related to a caravan hoax, where staff ultimately avoided arrest, illustrating ongoing tensions.

The conflict is part of a broader pattern, as recent incidents have seen staff from Premier Minns' and Police Minister Yasmin Catley's offices risk arrest for refusing to testify, highlighting ongoing tensions between government staff and parliamentary inquiries.

Legal experts, including Professor Anne Twomey, note that while Parliament has powers to seek arrest warrants for witnesses and enforce compliance, the constitutional and procedural implications of these powers remain highly contentious.

Premier Minns has criticized the committee's actions, describing the repeated inquiries involving staff as 'fishing expeditions' and suggesting they undermine judicial independence.