Church officials said they were putting off Monday's vote, in which they were widely expected to endorse bishop-elect Gene Robinson, to investigate two separate allegations of sexual misbehaviour.
Robinson had been elected the previous day by lower-ranking church representatives in Minneapolis, Minnesota.
“Questions have been raised and brought to my attention regarding the bishop-elect of New Hampshire,” said Frank Griswold, presiding bishop of the church's general convention.
One of the late-breaking allegations stems from an email sent to some of the bishops eligible to vote. The sender, identified as David Lewis from Manchester, Vermont, alleges that Robinson touched him inappropriately a couple of years ago.
The other allegation is that links to pornographic websites were recently found on the website of the New Hampshire chapter of Outright, a support group for gay and lesbian teenagers that Robinson founded. The links were removed earlier on Monday.
Late allegations suspicious
The Anglican gay rights group Integrity said it was confident that Robinson would be vindicated of all the charges levelled against him.
"We have complete confidence in the investigation the presiding bishop has put in place, and we fully expect the investigation will find the charges to be groundless," said Reverend Susan Russell, director of communications for Integrity.
Other clergy went further, suggesting the allegations, surfacing as they did at the eleventh hour, were extremely suspect.
"It is a little bit suspicious to me personally," Reverend Claiborne Jones told CNN. "It does certainly come at an inconvenient time for those that would like to confirm bishop-elect Robinson."
"This gentleman could have brought these charges months, years ago."
Even Robinson's critics sought to distance themselves from the charges.
"This is a very awkward thing," said Reverend Canon David Anderson, president of the American Anglican Council, a conservative splinter group that has opposed Robinson's elevation.
As an openly homosexual man who has lived with his partner for the past 13 years, Robinson has been the source of immense controversy in US Episcopalian circles and the more than 70 million-strong Anglican community worldwide.
Critics said the appointment would alienate believers and might even lead to a split in church ranks.
"It is an utterly unacceptable departure from doctrine," said Dr Kendall Harmon, a theologian and spokesman for conservatives. "This is a profound problem."
A 56-year-old, divorced father of two who has been in a
homosexual relationship for 13 years, Robinson had already won approval by a 2-1 margin in the church's House of Deputies in Minneapolis on Sunday.
Conservatives had pleaded his active homosexual relationship violated scripture and could shatter Anglican unity.
The bishops' vote on Monday was expected to be closer, but approval seemed certain until the last minute allegations.