In Australia, there are three different ways to get married. The Marriage Act 1961 allows for marriages to be solemnised by:

1. Ministers of religion of recognised denominations,
2. State and Territory Officers (most commonly at a State or Territory office of Births, Deaths and Marriages) and
3. Commonwealth-registered marriage celebrants. This category contains both civil (non-religious) celebrants (like me!) and ministers of religion who are not aligned with a recognised denomination.

There are 2 different sets of requirements, as set out in The Marriage Act 1961, that each group must abide by, to conduct a legally-binding marriage ceremony. Which, in essence, are via religious or civil rites;

1. Ministers of religion of recognised denominations and Commonwealth-registered marriage celebrants solemnising religious marriages may use any form of ceremony recognised as sufficient for the purpose by the religious body or organisation of which he or she is a minister.

This also means, if a couple wants to change the form of a religious ceremony, that the authorised celebrant (who is a minister of religion solemnising religious marriages) should seek formal approval for the change from their religious body or organisation.

2. Where a marriage is solemnised by or in the presence of a Commonwealth-registered marriage celebrant, not being a minister of religion, it is sufficient if each of the parties says to the other, in the presence of the authorised celebrant and the witnesses, the words:
“I call upon the persons here present to witness that I, <all legal names>, take thee, <all legal names>, to be my lawful wedded wife/husband.” or words to that effect.

In addition, all Commonwealth-registered marriage celebrants (therefore ministers of religion are exempt) solemnising civil or religious marriages are required to say to the parties, in the presence of the witnesses, the words:

“I am duly authorised by law to solemnise marriages according to law.
Before you are joined in marriage in my presence and in the presence of these witnesses, I am to remind you of the solemn and binding nature of the relationship into which you are now about to enter. Marriage, according to law in Australia, is the union of a man and a woman to the exclusion of all others, voluntarily entered into for life.” or words to that effect.

So the short answer is, unless you arrange for a minister of religion of a recognised denomination or a Commonwealth-registered marriage celebrant who solemnises religious marriages, you are under no (legal) obligation to include any religious content in your marriage ceremony unless you want to.

I have met several couples who, although their personal values and beliefs do not include those of a formal religion, would like to include religious aspects, like a simple ritual or short reading, in their ceremony. Sometimes it is to show respect to their parents and upbringing or as a nod to other religious family members. This is great, in my opinion. It is just another smart way to personalise your ceremony and stay true to your past and future selves.

Alternatively, if you are religious and your fiancé is not, you may choose to compromise and include both civil and religious material to reflect your individual beliefs. But, what is important to remember, is that the inclusion or exclusion of religious content is completely up to you.