Mr Shepherd said the school had a fully staffed science department but it was currently advertising for a mathematics teacher and was confident it would find somebody.
The school hadn't had issues with staff leaving for other industries, he said.
However, teaching was less attractive to people starting out in the workforce while many teachers were heading towards retirement.
"It is becoming a bit of an issue, but not a major issue yet," said Mr Shepherd.
"We're certainly an ageing profession. A lot of teachers are baby boomers basically. They started their teaching career in the seventies and are now heading towards the end of their careers.
"Our challenge is to make sure that there's good quality young graduates attracted into the industry."
Mr Shepherd said the answer was to pay more.
"That's basic. It's as simple as that."
The region's executive member for the PPTA Jack Boyle said remuneration hadn't kept pace with inflation in the teaching profession, meaning teachers were working more for less money.
Most teachers in the secondary workforce had at least a Bachelor's degree with a teacher training diploma or a four-year teaching degree, he said.
When they reached the workforce they earned less than those who had studied things such as law, accounting or medicine.
Mr Boyle said sciences, mathematics, technology and Maori were hard to staff across the country as were middle-management positions.
Recruitment into remote regions such as Wairarapa was also more difficult than in the major cities.
An ageing workforce would also result in staff shortages in more remote locations, he said.
The PPTA Secondary Staff Report was based on responses from 172 secondary and composite schools.
The report showed advertised jobs were increasing and the mean number of applicants per position was declining.
The proportion leaving to go to other jobs outside teaching had also increased.
Principals expressed reservations about the impacts of pending retirements on their schools.
Teachers were also leaving the state system for private schools, the report said.
Principals were, in general, less optimistic about retaining teachers and more pessimistic about recruiting.
Principals frequently mentioned maths, te reo, sciences and technology as hard-to-staff subjects. There were several references to the oversupply of physical education teachers.
There was a jump in teachers being used outside of their specialist area because specialists could not be found, according to the report.
Around one in nine schools had to cancel classes or transfer to a form of distance learning because a suitable specialist teacher could not be found, the report said.
