The Oscar-winning film director Charles Ferguson has cancelled his CNN documentary on Hillary Clinton after what he described as a private campaign against the film by prominent Democrats.

Ferguson said he had decided to pull the plug after being met with a wall of silence from more than a hundred people who refused to be interviewed for the documentary.

NBC also announced on Monday that it had cancelled a miniseries about Clinton due to be produced by its entertainment division. Both shows had caused controversy when they were announced earlier this year.

Ferguson claimed that aides to the former secretary of state put pressure on CNN behind the scenes, and made clear that Clinton would only co-operate "over my dead body". He also blamed a public campaign by Republicans, who claimed the film would be biased in favour of Clinton.

"Neither political party wanted the film made," said Ferguson in an article for the Huffington Post. "After painful reflection, I decided that I couldn't make a film of which I would be proud. And so I'm cancelling."

In a telephone interview with the Guardian, Ferguson said that he believed that much of early noise about the film, from both sides, was motivated by an attempt to stop people from contributing to the documentary. "I wasn't delighted, but it wasn't an issue of worry, because I've faced such things before, but I wasn't prepared for how effective it would be, that's what really surprised me," Ferguson said.

He blamed rejections on the desire of many potential contributors to work for, or gain access to, a potential Clinton administration. "Part of what's going on right now is that many, many, many people want to be in her campaign, they want a job in her administration, they want access to the White House, they want some specific thing that they care about and most of the people, probably over 90%, are going to be disappointed."

In his article, Ferguson, the director behind Inside Job and No End In Sight: The American Occupation of Iraq, claimed that Clinton's spokesman, Philippe Reines, had "interrogated" various executives at CNN about the documentary before it was announced by the broadcaster in July.

"When I approached people for interviews, I discovered that nobody, and I mean nobody, was interested in helping me make this film," said Ferguson.

"Not Democrats, not Republicans – and certainly nobody who works with the Clintons, wants access to the Clintons, or dreams of a position in a Hillary Clinton administration.

"Not even journalists who want access, which can easily be taken away. I even sensed potential difficulty in licensing archival footage from CBN (Pat Robertson) and from Fox. After approaching well over a hundred people, only two people who had ever dealt with Mrs Clinton would agree to an on-camera interview, and I suspected that even they would back out."

The campaign against the film began almost immediately after it was announced by CNN. The Republican national committee announced that its members would boycott the network over the Republican presidential primary debates in 2016.

"This did not surprise me. What did surprise me was that, quietly and privately, prominent Democrats made it known both to CNN and to me that they weren't delighted with the film either," said Ferguson.

Ferguson said he contacted several prominent Democrats following public criticism of his film by David Brock, the journalist and founder of the research group Media Matters for America.

"I told them that this campaign against the film and against CNN was counterproductive," he wrote. "They conveyed this message to Mrs Clinton personally, along with my request to speak with her. The answer that came back was, basically, over my dead body."

Ferugson said he had received support from CNN executives, including its president Jeff Zucker, about the "ambitious, controversial and highly visible" film – but added that the lack of cooperation from those close to Clinton meant he could no longer make make a documentary "of which I would be proud".

He added: "It's a victory for the Clintons, and for the money machines that both political parties have now become. But I don't think that it's a victory for the media, or for the American people.

"I still believe Mrs Clinton has many virtues including great intelligence, fortitude, and a deep commitment to bettering the lives of women and children worldwide. But this is not her finest hour."

Ferguson told the Guardian that hoped he could resurrect his project after the 2016 election. "After the election, no matter if she wins or loses – especially if she loses, but even if she wins – it'll be a lot easier to get access."

NBC Entertainment issued a statement saying that "after reviewing and prioritizing our slate of movie and miniseries development, we've decided that we will no longer continue developing the Hillary Clinton miniseries." The statement gave no reason for the change, and spokesman Richard Licata did not immediately return a call seeking comment, the Associated Press reported.

The announcement by NBC's entertainment division this summer that it was making "Hillary" took people in the network's news division by surprise. They were concerned that the news division would be blamed if the entertainment series took liberties with facts or leaned too far in making a positive or a negative portrayal of Clinton.

NBC News Washington correspondents Chuck Todd and Andrea Mitchell made their unease about the miniseries public.

