It's not easy to set up a date when you are twins.

But Australian sisters Lake and Flame have some relationship advice for loveless twins -- date your own kind.

The identical Brisbane twins, who do not use a surname, have launched what they call the world's first online matchmaking service for twins who want to find "love, marriage and fulfilment of their dreams."

"A lot of twins have trouble in relationships because their partners don't understand the closeness of their twin bond and so they get jealous," Twins Realm director Lake told Reuters on Thursday.

She launched online dating service Exclusively Twins www.twinsrealm.com with her mirror image twin Flame in January in the hope that "dating another twin could be the answer."

Members pay a subscription fee -- A$14.95 per month in Australia or US$9.95 overseas -- to access a database of twin singles from around the world.

"This is the only dating service in the world I know of that is exclusively for twins," Lake said, adding that around 30 identical or fraternal twins had already signed up, mostly from the United States.

Herself single, Lake lamented that so far there were no matchups. "But we're still in our infancy," she said.