Director of Public Prosecutions (DPP) Leanne Clare said that after discussions with the US lawyer, who will conduct the extradition application, additional statements had been sought from an expert witness relating to a number of the charges against Dr Patel.
"On the basis of the evidence from this witness, two charges of grievous bodily harm, and two charges of negligent acts causing harm would not proceed," Clare said.
But 16 charges remained active and would be pursued, news.com.au quoted Clare, as saying.
"They comprise three charges of manslaughter, three charges of grievous bodily harm, two charges of negligent acts causing harm, and eight charges of fraud," she added.
Dr Patel worked as Director of Surgery at Bundaberg Base Hospital in southeast Queensland before being named in state parliament, and fleeing to the United States in April 2005.
The health inquiry's notice to Dr Patel accuses him of conducting "surgical procedures that you had been restricted from performing in the US" and of performing "beyond your competence, skill and expertise".
It also accuses him of conducting highly complicated procedures, which were unnecessary and "beyond the capacity of the hospital and its staff", resulting in the death of 13 patients, and several other adverse outcomes.
Dr Patel's failure to report the 13 deaths to the coroner and record the true details in patient's files concerning infections, wound breakdowns, complications arising from surgery and the reasons for additional surgery has also been cited in the notice.
He has been linked to the deaths of 17 former patients at the hospital.