Auditor-General Greg Schollum says he will not be conducting an inquiry into the decision to grant citizenship to San Francisco-based billionaire investor Peter Thiel.

This comes in response to a request from Green Party MP Denise Roche.

A German citizen by birth and an American citizen by naturalisation, Thiel became a New Zealand citizen in 2011 and owns a 193 hectare estate near Lake Wanaka.