A powerful parliamentary committee investigating the chemotherapy dosing scandal at Sydney's St Vincent's Hospital will deliver a damning report, saying it cannot discount the possibility there was a cover-up.

The ABC has obtained a leaked copy of the committee's report into low doses of chemotherapy given to dozens of head and neck cancer patients by oncologist John Grygiel, who treated patients at St Vincent's and at cancer clinics in the state's central west.

It finds "the committee is not able to discount the possibility of a cover-up on the part of St Vincent's Hospital".

It also concluded that:

"...the hospital's senior management put their public standing ahead of the best interests of their patients as the matter unfolded and quickly became a full-blown scandal.

"[There were] elements of individual and collective human error, as well as systemic failures that contributed over time to the crisis that unfolded."

The committee found St Vincent's "failed to prevent and to respond effectively to the off-protocol prescribing of chemotherapy" but noted it has since taken responsibility for the failures.

"The hospital's key failures were that it did not escalate numerous concerns raised by staff for more than a decade, it did not understand the seriousness of the issue ... (and) it failed to grasp the imperative to act quickly," the report said.

Dr John Grygiel gave more than 100 patients less than the recommended dose of carboplatin. ( AAP: Dean Lewins )

The committee is also pushing for more transparency about how low dosing may have affected patients.

It recommends the Cancer Institute publish all evaluations of the outcomes for patients who received an off-protocol flat dose of 100 milligrams of carboplatin.

It is also calling for NSW Health to publish the result of a broader audit of public cancer patients across the state, which was ordered by former health minister Jillian Skinner.

The inquiry has also recommended that authorities ensure fly-in fly-out medical specialists, who service regional areas, are subject to the same safeguards as locally based clinicians.

The ABC understands some members of the committee had been pushing for stronger language, arguing the inquiry should find St Vincent's management and some senior doctors did initially seek to cover up the matter.

But that suggestion was over-ruled by the majority of the committee.

A push to bring the St Vincent's Health Network under closer scrutiny of NSW Health to ensure openness and transparency for patients was also overruled.

A spokesperson for St Vincent's told the ABC they reject the claims within the report "in the strongest possible terms".

"The exhaustive and independent Cancer Institute NSW inquiry did not produce any material to suggest anything of that nature had occurred.

"It found that Dr Grygiel's practice 'remained unknown to senior hospital management until August 2015'.

"The hospital acknowledges — and has publicly apologised — for the fact it failed to understand the seriousness of what had occurred and how this coloured its responses throughout, from the way management addressed the matter to its early public statements."

The spokesperson also said that NSW Health chief medical officer Dr Kerry Chant agreed with the Cancer Institute's findings before a parliamentary inquiry.