Whanganui High School hopes to appoint a new principal to start at the beginning of 2017 now that Garry Olver has announced his resignation.
Mr Olver, who became principal at the school in August 2012 has tendered his resignation to the school Board of Trustees after an 18 month period of health problems which have not shown any sign of "meaningful improvement."
Board spokesman Murray Woodhouse said Mr Olver has always strived to achieve the very best for the school community.
The board acknowledges his passion and concern for the success of both students and staff which has always been at the forefront.
Associate principal Elizabeth Spooner, who has provided extra support to students and staff during Mr Olver's illness will be acting principal until August 17 when an appointed interim principal will start work at the school.
"We have appointed a very good candidate and we will make an announcement about that shortly," said Mr Woodhouse.
"The last term of the year is always a busy and demanding one so this appointment has been made to support the staff until a permanent principal is appointed."
Mr Woodhouse said the board will be commencing the recruitment process for appointing a new principal, as soon as possible.