The Evangelical Alliance will call on Prince Charles to take the title 'Defender of the Faith' when he is crowned king. The EA will make the submission in its Faith and Nation report due to be launched today.
The Prince of Wales, who will become Supreme Governor of the Church of England when he is crowned king, has previously said he would like to be sworn as the 'Defender of Faith', meaning not any particular faith, taking into account the numerous religious groups represented in Great Britain.
But the Evangelical Alliance, which represents over one million Evangelical Christians in the UK, is calling for him to swear the traditional coronation oath to be 'Defender of the Faith' - specifically the Anglican Church.
The call is among 100 recommendations to be made, ranging from religious liberty and the environment to constiutional affairs.
Evangelical Alliance public policy director Dr David Muir said: "The report offers Christians, people of other faiths and those of no faith resources for engagement, discussion and action on a wide range of contempory issues.
"We hope the report will help people understand the continued importance of the Christian faith in 21st century Britian."
The Prince's remarks on his coronation oath have sparked controversy in the past.
Former Archbishop of Canterbury Lord Carey welcomed the proposed change, saying it would more adequately reflect the wide range of religions in the UK.
He said in June: "When the time comes for the next coronation there's got to be a number of changes. Very significant changes. The Queen came to the throne at a time when the Church of England was really the only Christian faith in the country.
"And there were no Muslims, Sikhs, Hindus around to be in any way evident in the life of the country. Now it's a completely different world, so the coronation oath would have to be looked at more critically.
"It's got to be a much more interfaith coronation service next time around. Prince Charles put his finger on it and there's no way in which the sovereign can be defender of one faith. Although I hope that the next coronation will say very firmly that Christianity is still the dominant faith of the United Kingdom... it's got to be a much more inclusive character."
But Dr Rowan Williams, current Archbishop of Canterbury, has warned in the past that Prince Charles should retain the original title.
Speaking in 2003 he said: "Unless something really radical happens with the constitution, he is, like it or not, Defender of the Faith and he has a relationship with the Christian Church of a kind which he does not have with other faith communities."
