Republican presidential candidate Ben Carson cannot tell for sure whether the Bible has authority over the American Constitution, drawing flak from Democrat supporters.

Carson, a devout Seventh Day Adventist, said the Bible's authority over the US Constitution actually depends on specifics in response to a question posted on social media.

"That is not a simple question. I think probably what you have to do is ask a specific passage of the Bible and a specific portion of the Constitution," Carson said, according to Washington Examiner.

"I don't think you can answer that question other than out of a very specific context," he told Chuck Todd of NBC News' "Meet the Press" on Sunday, according to News Max.

Occupy Democrats, an anti-Republican tea party group, criticised Carson for "failing miserably at answering what should've been a ridiculously easy question concerning the separation of the Church and the State."

"The Republican candidate looked visibly shaken and pathetically refused to answer the ridiculously easy yes-or-no question, instead mumbling on about unfairness and complexity of the question," the advocacy group said in its official website.

"Although he may be very good at performing brain surgeries, this Tea Party simpleton doesn't even understand one of the most basic tenets of our Constitution," the group added.

The retired paediatric neurosurgeon, who has been considered as a darling of Republican Tea Party, gave the interview a few days before the first Republican presidential debate on Aug. 6.

As one of 10 Republican presidential candidates with the highest average in national polls, Carson is expected to participate at the 9 p.m. event that will be aired on Fox News.

The primetime event will also feature real estate mogul Donald Trump, former Florida Gov. Jeb Bush, Wisconsin Gov. Scott Walker, Florida Sen. Marco Rubio, Texas Sen. Ted Cruz, Kentucky Sen. Rand Paul, former Arkansas Gov. Mike Huckabee, New Jersey Gov. Chris Christie and former Texas Gov. Rick Perry.

According to Politico, Fox News removed a requirement that participants must reach at least 1 percent in polling, allowing those who fail to make the cut for the Aug. 6 prime-time event to a 5 p.m. debate.

Ohio Gov. John Kasich, Rick Santorum and Louisiana Gov. Bobby Jindal, former HP CEO Carly Fiorina, former New York Gov. George Pataki and South Carolina Sen. Lindsey Graham will be relegated to the 5 p.m. event on Fox.