Krista Kach, 47, died following a 10-hour stand-off with police in Newcastle in September, after the bean-bag round punctured her body and impacted her heart.
The Law Enforcement Conduct Commission (LECC), which monitors all NSW Police investigations into so-called critical incidents, requested to view the force's manual guiding the use of such "less-lethal" measures.
Instead, NSW Police launched an appeal in the Supreme Court to stop it being compelled to produce the document in its entirety, arguing it contains sensitive information not relevant to the watchdog's probe.
The manual addresses more than the use of the bean-bag rounds and deals with police tactics and methodologies more generally, including those used by law-enforcement agencies overseas, the court was told on Thursday.
NSW Police counsel David Hume said the force respected the public-interest need for transparency, however there were legitimate concerns about the information being disclosed beyond the commission.
Police are also resisting an order to disclose personnel logs, which Mr Hume argued contained the names of operatives and could "lead to reprisals".
However, the commission argued those were not legitimate objections to handing over the material, the court was told.
Mr Hume conceded the commission is legally entitled to obtain documents in full which it deems relevant to its role of monitoring police investigations.
However, he argued a "public-interest immunity" should apply to parts of documents in which there is a greater public interest in not having them disclosed.
One of the concerns held by police was that the commission could pass on the information to state parliament, which could then make its way into a parliamentary report, or similar public disclosure.
"We did invite LECC to undertake not to on-disclose the information to parliament and that was refused," he said.
The three justices hearing the appeal questioned why the parties had been unable to reach an agreement to disclose only those parts of the document that relate to the use of bean-bag rounds.
Part of the agency's role is satisfying itself no elements had been overlooked, including material that might have been deemed irrelevant by police, the court heard.
The attorney-general's barrister James Emmett SC argued the commission should be able to see everything investigating police see, or as he put it be "inside the tent".
Mr Hume said the larger the tent, the greater the chance of leaks.
The issue being considered at the hearing was not only key for the existing case, but was also an "important and recurring issue" when it came to dealing with the relevant laws, Mr Hume said.
He argued the example of an informant providing information to police, which they were the powerless to stop being requested by the commission and disclosed to parliament and potentially further.
The case continues.
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