The Department of Conservation has confirmed a staff member who worked on the Ruataniwha Dam submission has resigned.

It comes after Radio New Zealand News revealed the department discarded a 50-page draft submission on the proposed water storage scheme in Hawke's Bay in favour of a few lines.

Photo: RNZ

The controversial draft submission said the dam could make the Tukituki River toxic and kill threatened fish species.

Radio New Zealand News understands a staff member resigned after that criticism was not included in the department's final submission, which was watered down to a few lines

A DoC spokesperson would not go into the reasons for the resignation last month, saying the department respects the privacy of the individual.

Meanwhile, DoC says it will review its handling of the submission, and investigate who leaked internal correspondence to Radio New Zealand News.

An internal email was also leaked that said Conservation Minister Nick Smith was concerned and wanted to see DoC's submission before it was presented.

A spokesperson for the minister says the investigation will who look into who leaked the original submission and the email to Radio New Zealand.

She says it will not be a witch hunt but about finding out whether the leaks are systemic.

Dr Smith met DoC staff on Tuesday to review the handling of the submission.

He said before the meeting internal issues within DoC needed to be resolved relating to the management of the submission and finding out why senior managers did not know until late in the process there were differences of opinion.