BackgroundMany countries are looking for ways to increase nurse practitioner (NP) and physician assistant/associate (PA) deployment. Countries are seeking to tackle the pressing issues of increasing healthcare demand, healthcare costs, and medical doctor shortages. This article provides insights into the potential impact of various policy measures on NP/PA workforce development in the Netherlands.MethodsWe applied a multimethod approach study using three methods: 1) a review of government policies, 2) surveys on NP/PA workforce characteristics, and 3) surveys on intake in NP/PA training programs.ResultsUntil 2012, the annual intake into NP and PA training programs was comparable to the number of subsidized training places. In 2012, a 131% increase in intake coincided with extending the legal scope of practice of NPs and PAs and substantially increasing subsidized NP/PA training places. However, in 2013, the intake of NP and PA trainees decreased by 23% and 24%, respectively. The intake decreased in hospitals, (nursing) home care, and mental healthcare, coinciding with fiscal austerity in these sectors. We found that other policies, such as legal acknowledgment, reimbursement, and funding platforms and research, do not consistently coincide with NP/PA training and employment trends. The ratios of NPs and PAs to medical doctors increased substantially in all healthcare sectors from 3.5 and 1.0 per 100 full-time equivalents in medical doctors in 2012 to 11.0 and 3.9 in 2022, respectively. For NPs, the ratios vary between 2.5 per 100 full-time equivalents in medical doctors in primary care and 41.9 in mental healthcare. PA-medical doctor ratios range from 1.6 per 100 full-time equivalents in medical doctors in primary care to 5.8 in hospital care.ConclusionsThis study reveals that specific policies coincided with NP and PA workforce growth. Sudden and severe fiscal austerity coincided with declining NP/PA training intake. Furthermore, governmental training subsidies coincided and were likely associated with NP/PA workforce growth. Other policy measures did not consistently coincide with trends in intake in NP/PA training or employment. The role of extending the scope of practice remains to be determined. The skill mix is shifting toward an increasing share of medical care provided by NPs and PAs in all healthcare sectors.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12913-023-09568-4.