The most effective way to manage the public service was fiscal discipline and accountability.
"Lifting the cap creates incentives for agencies to find efficiency savings. It's up to agency chief executives to demonstrate why they can no longer manage within existing budgets."
National's State Services spokesman Nick Smith said the move risked a blowout of the public service.
"Between 2003 and 2008 under Labour, public service expenditure grew by 50 per cent with no improvement in outcomes for New Zealanders.
"Today's announcement carries the risk that we'll see another blowout of the public service and taxpayers' money will again be frittered away on pointless bureaucracy," he said.
"The previous National government introduced the cap on the number of core public service staff so that public sector agencies would have to work smarter and more efficiently, and ensure that taxpayers' dollars were spent more wisely."