Two months after his inauguration, Mayor Bill de Blasio’s government is still a work-in-progress.

Of 41 top-level agency posts that report to the mayor — those identified in the Mayor’s Management Report — only 20 or about half of them had been filled as of Friday. Three others, including the Fire Department and Department of Sanitation, are being filled by holdovers from the Bloomberg administration.

On Friday, De Blassio argued that there was a "fairly small number of agencies left that we have to name people to."

Back in December, critics were already highlighting the slowest rollout of a new city government in recent memory.

Even with the slow pace of appointments, many advocates are wary of criticizing the mayor.

“I think he’s chosen a lot of good people,” said Gene Russianoff, of the New York Public Interest Research Group, a good-government group. “The deliberations have resulted in candidates that benefit the city.”

Russianoff, who served on a subcommittee of de Blasio’s transition team, added, “At some point it will be too long. But I don’t think we’re there yet.”

These are some of the unfilled posts:

Department of Information Technology & Telecommunications

Why it matters: It’s the lead agency for pioneering efforts to improve delivery of government services through information technology.

John Kaehny, the executive director of Reinvent Albany, an organization that works at the city level to advocate for a more transparent government through the use of technology, said he was pleased with de Blasio’s recruitment process so far. “They have set the bar pretty high,” he said.

Department of Parks and Recreation

Why it matters: The agency manages the city’s 1,900 parks and public recreation facilities.

“There are a lot of issues that are outstanding. And they need to be addressed,” said Geoffrey Croft, of New York City Park Advocates, who said his organization was waiting anxiously for de Blasio to name a parks commissioner.

He points to the long-running fight over whether to allow a high-end restaurant in the pavilion at Union Square Park that was pushed by the Bloomberg administration as an example.

“We’ve been waiting for months and we want to know where the mayor is going on these very important issues,” Croft said. “Is de Blasio going to continue this or make a break with these irresponsible policies and start being progressive?”

Landmarks Preservation Commission

Why it matters: It extends protections to historically and architecturally significant structures.

Andrew Berman, the executive director of the Greenwich Society for Historic Preservation, said his organization is anxiously waiting for a new chair to be appointed. Nevertheless, Berman said the “commission is remaining active.”

“They are certainly not sitting on their hands,” though he added that “there are a lot of things we’d like to see the commission take on and that it has not.”

“In general, you want certainty. You want to know who you are dealing with,” Berman said.