Some 100 Hawaii clergy and other potential officiants have learned how to obtain online licenses to perform civil unions beginning just after midnight Sunday, offering a hint of the potential scope of civil unions in the islands.

Separately, the state Health Department has no way of knowing how many same-sex couples plan to apply for civil union licenses when they also become available after midnight Sunday, spokeswoman Janice Okubo said.

But Jan. 1 will mark the realization of a decades-long movement by gay rights advocates that fell short of legalized marriage for same-sex couples in Hawaii but nonetheless will represent a historic moment. In February, gay rights advocates celebrated as Gov. Neil Abercrombie signed into law a bill making Hawaii the seventh state to legalize civil unions.

"The legalization of civil unions in Hawaii represents in my mind equal rights for all people," Abercrombie said when signing civil unions into law.

The law allows all couples — same-sex and heterosexual — to enter into a civil union, a legal status with all the rights, benefits, protections and responsibilities as traditional marriage.

The Rev. Kyle Lovett of the Church of the Crossroads underwent the Health Department’s online application training for civil union clergy licenses last week, and said she was impressed that so many other potential officiants were also being trained.

"For a state this size, that’s a statistically significant number," she said.

State registrar Alvin Onaka trained about 50 potential civil union officiants last week and had two more online training sessions Tuesday for another 50 or so participants.

The number offers a glimpse of the potential scope of the demand in Hawaii for civil unions — but most likely underrepresents the true number of people who will actually officiate at the ceremonies because it’s easy to get a license online, Okubo said.

"It’s a pretty simple process, but some officiants might just want to make sure," Okubo said.

Lovett, the Rev. Jonipher Kwong of the First Unitarian Church of Honolulu and possibly two other officiants will preside over a civil union ceremony for four same-sex couples just after midnight Sunday that organizers hope will be the first official ceremony of its kind in the islands.

The ceremony will be held at an undisclosed home in East Honolulu.

It will begin with all of the parties going online on separate computers to receive their various licenses from the Health Department’s website, Lovett said.

Lovett said the online licensing process should take no more than 31/2 minutes per person.

"It’s very, very, very simple," she said.

But Kwong expects a few computer glitches.

"I am anticipating a few kinks, which is true of any transition — especially when it comes to the way bureaucracy works," Kwong said. "What’s more important is the sense of excitement the couples have to do this: To protect their families and profess their love for one another in such a public way. To me that’s the most important part. We can all work our way around the technical aspects."

But Kwong hopes any unanticipated problems don’t take long to resolve.

"I have a 10:15 service to attend later that morning," he joked, "so I want to get some sleep in."

The ceremony will be witnessed by 75 to 100 guests, according to Tambry Young, president of Citizens for Equal Rights, who is helping with the plans.

"We want to be the first state in 2012 to enact our civil unions law with these ceremonies," Young said.

Gary Bradley and Paul Perry will be among the first couples in the state to enter into civil unions.

"We are making this commitment as we love and care for each other very much," the couple said in a statement Tuesday provided by Citizens for Equal Rights. "This is just one step closer to full marriage equality and recognition at the federal level which we strive for."

The Waikiki couple will be joined by Donna Gedge and Monica Montgomery, and Saralyn Batt and Isajah Morales.

"It was important to us to have our civil union as soon as the law allowed it," Batt and Morales said in the statement.

The fourth couple wants to remain anonymous.

A Honolulu bakery is donating a cake for the event, and a Honolulu salon is providing hairstyling for the couples.

Couples need to fill out an online application to have a civil union ceremony and be issued a temporary civil union certificate, Okubo said.

Health officials will later review the couples’ and officiants’ applications and then mail a permanent civil union certificate within 30 days if everything is proper, Okubo said.