Caroline Kennedy was among the candidates purportedly rejected
White House officials have denied any candidates have been proposed for the post of US ambassador to the Vatican.
A senior White House official told the BBC that they had "not floated any names with the Vatican".
The news follows reports that at least three candidates had been informally proposed by the Obama administration but rejected by the Vatican.
The candidates were said to have been unacceptable because of their support for abortion rights.
One of those named a potential candidate was Caroline Kennedy, daughter of the former US president.
Conservative Catholics in the US had already criticised her candidacy, saying her outspoken pro-choice views on abortion made her an unsuitable choice.
The Vatican is unhappy about President Barack Obama's support of abortion rights and his lifting of a previous ban on embryonic stem cell research in the US.
Vatican spokesman Father Federico Lombardi has described media speculation about the selection of the next US ambassador to the Holy See as "unreliable".
He said that the US had not yet officially submitted any names.
Since the US established formal diplomatic relations with the Vatican in 1984, the ambassadorial post has always been held by pro-life Catholics under both Republican and Democrat administrations.
The ambassador will replace Mary Ann Glendon, a Harvard University professor who held the post during George W Bush's presidency.