Ngouboua is home to displaced Chadians as well as Nigerian refugees who have fled the violence in Islamist group Boko Haram's strongholds in northeast Nigeria, and the insurgents have attacked it several times in the past year.
The two bombers also died in the twin blasts in Ngouboua, a fishing village on the shores of Lake Chad.
"I can confirm that there was an attack in Ngouboua," said national police spokesman Paul Manga, who added that both bombers were believed to have been women, but gave no further details.
The number of those killed was provisional and could rise, he said.