Manchester, New Hampshire (CNN) Bernie Sanders complained on the campaign trail Friday that dialing for dollars "affects your entire being."

What he didn't mention: The Vermont senator and presidential candidate is a prolific fundraiser himself and has regularly benefited from the Democratic Party apparatus.

In recent years, Sanders has been billed as one of the hosts for the Democratic Senatorial Campaign Committee's retreats for the "Majority Trust" -- an elite group of top donors who give more than $30,000 per year -- at Martha's Vineyard in the summer and Palm Beach, Florida, in the winter. CNN has obtained invitations that listed Sanders as a host for at least one Majority Trust event in each year since 2011.

The retreats are typically attended by 100 or more donors who have either contributed the annual legal maximum of $33,400 to the DSCC, raised more than $100,000 for the party or both.

Sanders has based his presidential campaign on a fire-and-brimstone critique of a broken campaign finance system -- and of Hillary Clinton for her reliance on big-dollar Wall Street donors . But Sanders is part of that system, and has helped Democrats court many of the same donors.

A Democratic lobbyist and donor who has attended the retreats told CNN that about 25% of the attendees there represent the financial sector -- and that Sanders and his wife, Jane, are always present.

"At each of the events all the senators speak. And I don't recall him ever giving a speech attacking us," the donor said. "While progressive, his remarks were always in the mainstream of what you hear from senators."

Sanders' political leanings were well known by the donors who attended the retreats. "Nobody was more surprised that Bernie was there than the donors were," said another Democrat who attended the retreats.

But Sanders maintains that members of Congress now spend far too much time making calls seeking campaign contributions -- or "dialing for dollars," he said during a speech at the New England Council's "Politics and Eggs" event Friday morning.

"That's what they do. And not only should members who are elected be working for the people, not raising money -- if you think you could simply divide your brain in half, if you're working on unemployment or health care and think, now I've gotta go out and raise money, it affects your entire being," he said.

Benefits from Democratic establishment

Sanders has been an Independent while in Congress, but has caucused with the Democrats since he was elected to the Senate in 2006, helping them maintain their majority for eight years.

Michael Briggs, a Sanders spokesman, said Sanders has "raised more money for the Senate Democrats than almost any other member of the Senate Democratic caucus" because he sees helping the party regain the majority as critical.

"He has in the past written letters and helped Senate Democrats elect Democrats. He thinks that's very important to the country," Briggs said.

He got a hand from the party in 1996, when Rob Engel, then the political director for the Democratic Congressional Campaign Committee, pushed a Democratic contender out of the race for the House seat Sanders held as an independent.

In 2006, when Sanders ran for the Senate, the Democratic Senatorial Campaign Committee pumped $37,300 into his race and included him in fundraising efforts for the party's Senate candidates.

The party also spent $60,000 on ads for Sanders, and contributed $100,000 to the Vermont Democratic Party -- which was behind Sanders even as he ran as an independent.

Among the DSCC's top contributors that year: Goldman Sachs at $685,000, Citigroup at $326,000, Morgan Stanley at $260,000 and JPMorgan Chase & Co. at $207,000.

During that 2006 campaign, Sanders attended a fundraiser at the Cambridge, Massachusetts home of Abby Rockefeller -- a member of the same family whose wealth he had one proposed confiscating.

Two years later, when then-Illinois Sen. Barack Obama was being nominated at the Democratic National Convention in 2008, Sanders was among the senators who met with Sen. Chuck Schumer's "Legacy Circle" donors who had given the legal maximum to the DSCC five years in a row or $500,000 over their lifetimes.

He paid dues to the DSCC, too, with his Progressive Voters of America political action committee cutting checks for $30,000 to the group during the 2014 election cycle.

Broken system?

Sanders told the "Politics and Eggs" crowd that he favors a public financing system for elections, eliminating campaign contributions entirely. But his presidential campaign, just as Clinton's and Barack Obama's in 2008 and 2012, has chosen to bypass that system, allowing Sanders to raise millions of dollars more.

He has repeatedly touted his campaign's vast online fundraising apparatus, which has pulled in 3.5 million individual contributions, averaging $27 apiece, Sanders said Friday.

Pressed by MSNBC moderator Chuck Todd on why he hasn't accepted public financing in Thursday night's debate, Sanders said the system as it exists now is "a disaster" and "very antiquated" because it limits spending in early-voting primary states.

"The way it is structured right now, if you make it all the way to California, you could do pretty well. But in terms of the early states -- Iowa, New Hampshire, the other states -- it just doesn't work," Sanders said.