"I stand by the story," wrote Simon Denyer, the Post's India bureau chief and author of the story, in a blog post Wednesday in response to a complaint from Pankaj Pachauri, communications adviser at the Prime Minister's Office.
"My apology was for the fact that the website was down and the PM's office could not post a reply directly. As soon as the problem was fixed, I informed them," added Denyer.
In a front page story Wednesday, the Post had called Manmohan Singh "a dithering, ineffectual bureaucrat presiding over a deeply corrupt government" and quoted sources who described a man "fatally handicapped by his timidity, complacency and intellectual dishonesty."
Responding to the Post article, Pachauri in a letter to Denyer, wrote: "We do not complain about criticism of the government which is a journalist's right. But I am writing this letter for pointing out unethical and unprofessional conduct at your part."
In his complaint, the official said: "Despite all lines of conversations open, you never got in touch with us for our side of the story though you regularly talk to me about information from the PMO. This story thus becomes totally one sided."
Pachauri told Denyer that when he rang him to point out that his request for an interview was declined "till the Monsoon Session" of the Parliament which gets over in two days, "you said sorry twice though you tell the media here that you never apologised."
"The former media adviser to the PM Dr Sanjaya Baru has complained that you 'rehashed and used' an 8 month old quote from an Indian magazine," he added.
Denyer responded saying when his third request for an interview with the PM was declined on July 30 "there was no mention of the possibility of an interview afterwards."
"In any case my story touches on the fact that parliament has been adjourned every day throughout the current session by opposition calls for the PM to resign, which is a story I felt should be told, interview or not," Denyer wrote.
But the correspondent acknowledged that the comments attributed to Baru and political historian Ramachandra Guha were originally published in the Caravan, an Indian magazine, in 2011 and ran a corrected version of the article.
"While both men told The Post that the assertions could accurately be attributed to them, the article should have credited the Caravan when it used or paraphrased the remarks," it said.
In another blog, the Post said the story had received a mixed bag of "more than 600 comments online, earned a slew of tweets from both defenders and detractors and sparked several articles in Indian newspapers."