Arrangements will start within the next few days to pass a law to give create the Constitutional amendment that will allow Ireland's first same-sex marriage to take place before Christmas.

The expected Yes vote will result in a new sentence being added to Article 41 of Ireland's Constitution. It will read: "Marriage may be contracted in accordance with law by two persons without distinction as to their sex."

The Gaelic version reads: "Féadfaidh beirt, gan beann ar a ngnéas, conradh pósta a dhéanamh de réir dlí." Which translates that a marriage between two people of the same sex will now be recognised by the State and will have the same status under the Constitution as a marriage between a man and a woman.

To give effect to the amendment, the Oireachtas (Ireland's parliament) will enact the Marriage Bill 2015, which will state in law that being of the same sex is no longer an impediment to marriage.

Officials in the Department of Justice are due to start the drafting the legalisation next week. A spokesman said the Bill would be ranked with a view to it being passed by the Oireachtas before the summer recess.

The law will set out the practical changes to come. When it comes into place, two people getting married will declare that they accept each other as "husband and wife" or as "spouses of each other". It will also state that a change of gender will have no effect on marriage.

There will be no new civil partnerships from the day the law comes into effect. Existing civil partnerships will hold the status and the rights, privileges, obligations and liabilities that go with it unless they choose to marry, but there will be no automatic "upgrade" from a partnership to marriage.

If couples decide to get married, their civil partnership will be automatically dissolved.

The law will also state that religious solemnisers will not be obliged to marry a same-sex couple, and that the same prohibited degrees of relationship will apply to same-sex marriages as to opposite-sex marriages.

When the Marriage Bill has been drafted, it will go to Cabinet for a formal sign-off. It will then be enacted by the Oireachtas – probably in July – before practical work is done on changing marriage forms and procedures.

Lastly, the Minister for Justice will sign a commencement order.