Michael Dennis Bush CNZM is a retired New Zealand police officer. He served as the New Zealand Commissioner of Police from April 2014 until April 2020.

Bush joined the New Zealand Police in 1978, working at both CIB and Frontline Policing. As he progressed through the ranks he was appointed to senior roles, including Liaison Officer for South East Asia. This position was held by Bush at the time of the 2004 Boxing Day tsunami. He was the first New Zealand official on the scene of this incident, arriving on Phuket to assist with relief.

In the 2006 New Year Honours, he was appointed a Member of the New Zealand Order of Merit (MNZM) for his relief work. He was also awarded the New Zealand Special Service Medal (Asian Tsunami) recognising this work.

Upon appointment to the role of Commissioner of Police in 2014, Bush made several changes focused on operational models and culture. These included the introduction of a "Prevention First" operating model, where the primary focus of policing resources would be on crime prevention. Bush introduced additional core values of "Empathy" and "Valuing Diversity" in an effort to make cultural changes following the 2007 Commission of Inquiry into Police. Bush was reappointed to the role of commissioner in 2017 for a second term that ran until April 2020.

In the 2020 Queen's Birthday Honours, Bush was promoted to Companion of the New Zealand Order of Merit, for services to the New Zealand Police and the community. The COVID-19 pandemic reached New Zealand at the end of Bush's tenure as Police Commissioner. Bush was appointed to lead the operational arm of the COVID-19 All-of-Government Response Group on 23 March 2020 and continued to hold this role after retiring from the New Zealand Police in April 2020.

Since leaving the police, Bush has been working as a private investigator.