PINS announced the recruitment drive this week and said it wants new inspectors "at the most senior levels" to help "improve service for customers".
In a statement, PINS said inspectors are home-based and operate nationally and may stem from a variety of professional backgrounds, including planning, law, local government, architecture, engineering, academia and environmental.
Operating on behalf of the secretary of state for housing, communities and local government, it said inspectors' roles involve: determining planning and enforcement appeals; examining development plans for local authorities; and making recommendations on applications for nationally significant infrastructure projects.
The recruitment drive follows a key recommendation in a government-commissioned review of the appeal inquiry process by economist Bridget Rosewell.
Rosewell's report, published in February, found widespread concern from industry bodies that a shortage of inspectors was contributing to delays in the appeals system.
She said that PINS was failing to "recruit sufficient inspectors to replace the loss of experienced staff" and called for the inspectorate to prepare an action plan to boost its staffing levels.
Sarah Richards, PINS chief executive, said, "Increasing the number of planning inspectors, who decide and examine the complex casework we deal with, is vital to our important role in the planning system.
"Over the past few years, we have seen a large increase in the demand for our services. With the high number of major infrastructure applications expected over 2019 and 2020 and the continuing demand for decisions on complex planning appeals, recruiting new inspectors is one of the measures we are taking to meet demand."
PINS said applicants must apply by 30 May. More details can be found here.