Atheists in the US are demanding an apology from a university chancellor who suggested religion is fundamental to a functioning democratic society.

Jack Hawkins, the chancellor of Alabama’s Troy University, sent his students and staff a video about "religious freedom" as part of an end-of-year message, AL.com reported.

But American Atheists, a group that campaigns for the absolute separation of government and religion, criticised Hawkins for implying that those who do not believe in God cannot be "moral, law-abiding citizens".

In the 90-second clip Clay Christensen, a professor at Harvard Business School, details a conversation he had with a Marxist economist from China, in which the other man said democracy works because people believe that "they aren’t just accountable to society, they’re accountable to God".

Christensen then asks: "As religion loses its influence over the lives of Americans what will happen to our democracy?

"Where are the institutions that are going to teach the next generation of Americans that they, too, need to voluntarily choose to obey the laws. Because if you take away religion you can’t hire enough police."

In the letter of complaint, which was published by AL.com, David Silverman, president of American Atheists, said that the organisation was contacted by a student at the university who was concerned by the content of Hawkins' message.

Silverman stated: "The video asserts that religion, particularly Judeo-Christian beliefs, are necessary to be moral, law-abiding citizens, and implies that those who do not attend church will be anti-democracy and anti-social members of society."

He called for an apology from Hawkins, writing: "On behalf of the student who contacted us, the Alabama members of American Atheists, the thousands of atheists at Troy University, and the hundreds of millions of atheists worldwide who live productive, law-abiding lives without religion, we demand an apology from you for using the public university email system and your publicly funded position to disparage atheists and minority religious groups as well as perpetuating the discrimination and anti-patriotic sentiment against atheists in the United States."

He then went on to suggest that atheists statistically lead more fulfilling lives, before inviting Hawkins to attend the organisation’s annual national convention in Memphis in April, "to experience for yourself what atheism and atheists are like".

According to a Gallup survey, Alabama is the second-most religious state in America, behind Mississippi and in joint place with Utah. Around 86 per cent of people in the state identify as religious, with 56 per cent saying they are very religious. The vast majority are Protestant.

It is unclear whether Hawkins has seen the letter.