Clinton's campaign criticized Trump on Saturday for inviting Flowers, with whom former President Bill Clinton admitted having "sexual relations" with at least once when he was attorney general of Arkansas during the 1970s.
The bipartisan Commission on Presidential Debates has ruled that presidential debate moderators should act as facilitators of conversation and only occasionally intervene during confrontations between the candidates.
"I can not confirm that", Conway said. He said Trump's tweet, hinting at a Flowers' invitation, was intended "to mock an effort by Hillary Clinton and her campaign to really distract attention from where the people - the American people are going to be focused tomorrow night, which is on the issues, it's on the choice that we face".
She has been focusing on his psychological profile, with a goal to get Trump to crack, to show that he can't control himself and lacks the even-handed temperament a president needs.
As Trump campaigned in the battleground state of Virginia, Clinton stayed close to home in NY while preparing for Monday night's opening debate.
That's according to Trump's campaign manager, Kellyanne Conway. And any slip is sure to be a TV news sound bite. On Friday he won the endorsement of former conservative rival Senator Ted Cruz. But he continues with campaign rallies on other days, including Saturday night in Roanoke, Virginia. Clinton's camp confirmed this week that it would invite billionaire mogul Mark Cuban, a Trump antagonist, to the debate.
However, Conway followed up that appearance by telling ABC's This Week that Flowers has every right to attend "if someone else gives her a ticket".
Presidential candidates Hillary Clinton and Donald Trump are expected to meet separately in NY with Israeli Prime Minister Benjamin Netanyahu.
Clinton, making her second presidential bid, is an old hand at debates and considered solid.
After nearly 40 years of public service, she is very well versed on the issues, and 88 per cent of Americans believe she is smart.
The ABC News/Washington Post survey put Clinton ahead of Trump, 49 percent to 47 percent, well within the poll's margin of error of 4.5 percentage points. And 52 per cent have a negative opinion of a woman they see as cerebral, distant or cold. The Israeli leader has sought to project neutrality this time after perceptions arose that he favored Mitt Romney over President Barack Obama in 2012.
But on Saturday, Trump tried to argue that Clinton had failed in her objectives.
Kaine has said of Clinton: "When the spotlights are at the brightest and the pressure is the most intense, that's when she brings her A-plus game". It is expected to be the largest national audience for a presidential debate - in a race that is one of the closest in recent years. He is good on his feet, and unpredictable, more comfortable in the limelight than on issues.