John McCain, who has based much of his political career and his presidential candidacy on his high ethical standards, faces a new set of questions about his ties to the lobbying industry that he has decried publicly.

The Washington Post details in a story Friday how a number of top McCain campaign advisers -- including campaign manager Rick Davis, chief political adviser Charles Black, and senior advisers Steve Schmidt and Mark McKinnon -- either have worked as lobbyists for major corporations, or work for lobbying firms.

The article notes that McCain also has hired a former lobbyist as his Senate office chief of staff -- Mark Buse -- and his chief presidential campaign fundraiser also is a lobbyist: former Texas Rep. Tom Loeffler.

McCain said Friday that while lobbyists serve as close advisers to his presidential campaign, they are honorable and he is not influenced by corruption in the system.

"These people have honorable records, and they're honorable people, and I'm proud to have them as part of my team," McCain told reporters following a town hall meeting in Indianapolis.

The focus on McCain's lobbyist relations comes a day after The New York Times published an article inferring improper behavior in connection to a female lobbyist, going so far as to say some aides were concerned during McCain's 2000 bid for president that the two were having a romantic relationship. The article provided no evidence of such a relationship, and both McCain and the lobbyist, Vicki Iseman, have denied anything more than a friendship.

McCain and his advisers roundly dismissed the allegations in the Times piece, calling it a tabloid-journalism political smear not based on substance, and ignoring facts provided by the McCain campaign.

In response to the Post's inquiries, Black said he continues to manage his lobbying firm, BKSH and Associates, where he is chairman, but he said he recuses himself from discussions between himself and McCain on which his clients have hired him.

Davis did not speak with the Post, but Black said Davis was not being paid by the firm Davis works for or by the McCain campaign -- which was in financial deep water last year, and learned Thursday that it could find new troubles due to an unfavorable opinion from the Federal Election Commission.

Schmidt and McKinnon said they are not lobbyists although they continue to work for lobbying firms. They, too, said they recuse themselves on potentially conflicting matters.

Click here to read the full report in The Washington Post.

The Associated Press contributed to this report.