At least 100 couples are expected to create a Valentine's Day they'll remember, by saying "I do" in ceremonies across NSW on Tuesday.

The NSW Registry of Births, Deaths and Marriages estimates that more than 200 people will marry in NSW on February 14.

Thirty-five of those couples will wed at the state's registry offices, with 19 choosing to tie the knot on Tuesday at the Sydney office in Chippendale, according to NSW Registrar Greg Curry.

"Valentine's Day is busy here at the registry with so many couples getting married," Mr Curry said in a statement.

"We try to make it a special and memorable day for each couple."

While the registry supplies the vows and the venue, couples often add a personal touch, with brides arriving by limousine, taxi or on the back of a growling Harley-Davidson, Mr Curry says.

Bride's outfits range from the traditional, such as the big white dress or an Indian sari, to something casual.

Mr Curry says registries are becoming more popular because they offer an inexpensive alternative to the big white wedding.

In 2001 civil marriages made up just over half of all of the state's ceremonies. A decade later, in 2011, they made up nearly 67 per cent.

Although Valentine's Day has become a celebration of romance for some, Lyn Fletcher from Relationships Australia NSW says not everyone embraces the outpouring of stuffed animals, flowers and chocolates.

"For many people, celebrating Valentine's Day is an important way of injecting romance ... for others the day is a load of old rubbish and just another sentimental fad Australians have imported from the US," Ms Fletcher said in a statement.

"And then there are those who sit somewhere in between."

Ms Fletcher encourages couples to understand each other's expectations about the day, in case one partner is dreaming of a candle-lit dinner or a giant teddy bear.