Pope Francis is leading the Catholic Church into heresy, according to more than 60 conservative scholars and priests.

In an extraordinary move the academics signed a formal 'filial correction', last made to a sitting pontiff in 1333.

The 25-page document accuses Francis propagating heresies over marriage, the moral life, and the sacraments. Entitled Correctio filialis de haeresibus propagatis, meaning 'A Filial Correction Concerning the Propagation of Heresies,' it was delivered to the pope at his Santa Marta residence on August 11, according to the National Catholic Register.

It is signed by a number of prominent Catholic intellectuals including German academic Martin Mosebach, former president of the Vatican Bank, Ettore Gotti Tedeschi, and the superior general of the Society of St. Pius X, Bishop Bernard Fellay.

The 62 signatories accuse the Pope of holding seven heretical positions on 'marriage, the moral life, and the reception of the sacraments' which, they say, has 'caused these heretical opinions to spread in the Catholic Church.'

They 'respectfully insist' the Pope condemns these heresies he has held either directly or indirectly and return to what they see as the true Catholic faith.

It comes after a letter last year asked the College of Cardinals to request the Pope condemns certain heresies. Then four cardinals issued a 'dubia', or letter of questioning, to the Pope in May over uncertainties about his Amoris Lautitia teaching document.

But this new letter raises tensions with its unprecedented rebuke to Francis.

'With profound grief, but moved by fidelity to our Lord Jesus Christ, by love for the Church and for the papacy, and by filial devotion toward yourself, we are compelled to address a correction to Your Holiness on account of the propagation of heresies effected by the apostolic exhortation Amoris laetitia and by other words, deeds and omissions of Your Holiness,' it begins.

The letter stresses it is not accusing Francis of the formal Catholic sin of heresy but they also cite a number of examples where they say it is 'beyond reasonable doubt' that the Pope 'wishes Catholics to interpret these passages in a way that is, in fact, heretical.'

The Pope's Amoris laetitia addressed controversial topics such as Communion for divorced and remarried couples and was interpreted by some as permitting those in second marriages to join the Eucharist.

The signatories warn there is a double 'danger' for Catholics as they will either support false teaching, or they will deny the Pope's infallibility as Supreme Pontiff.

You can read the letter in full here.