 -- The temporary across-the-board federal hiring freeze that President Donald Trump ordered in one of his first executive actions will end Wednesday and be replaced with a narrower halt on new government employment.

Mick Mulvaney, the director of the Office of Management and Budget, described the new stay on hiring as a more "surgical" freeze than the first.

"This is a big part of draining the swamp," he said. "Really what you're talking about doing is restructuring Washington, D.C., and that is how you drain the swamp, so this is a centerpiece of his campaign and a centerpiece of his administration."

Mulvaney told reporters Tuesday that the new administration guidance — which he called the Smart Hiring Plan — will go into effect at federal agencies Wednesday and will result in some agencies having the flexibility to hire while others may need to trim further, depending on where the particular agency falls in Trump's budget priorities.

While a department like the Environmental Protection Agency will likely need to look at reducing its workforce to comply with the president's budget priorities, Mulvaney said, the Departments of Defense and Veterans Affairs might be able to hire more workers. He also said that there is potential for some programs to move from one agency to another.

Though Mulvaney said the government workforce is set to shrink, he did not divulge a specific number of jobs that could be on the chopping block. It will be up to the affected agencies to offer plans for how they will comply with the new guidance.

"We think we could run the government more efficiently than the previous administration," he said. "And we think we can run the administration with fewer people than the previous administration."

Asked about a potential negative impact on the morale of the federal workforce as a result of the administration's actions, he said hard-working federal employees shouldn't be worried.

"One of the frustrations that government workers have is that we don't reward those who do a really good job and we don't punish those who do a lousy job," said Mulvaney, who emphasized that the administration's plan is not to shrink the government as small as possible but to eliminate inefficiencies.

"This is about good government. It's not about big government. It's not about small government. It's about good government," he said. "And what the businessman in chief has essentially come to us and said [is to] make sure this government functions properly."

Under the executive guidance, agencies will have until June to develop preliminary plans to comply. Those plans will be finalized and submitted to Trump in September, Mulvaney said.