"Last year there were 10 applicants, and the year before last, five" spokeswoman Irina Ozarchuk said.
However, she said officials face technical difficulties in legally changing peoples' genders.
Some applicants come to the register office without having had sex-change operations, and with no official documents confirming that the change has been medically approved, she said. The applicants also want their names and surnames changed.
"We are only a registering organization, not a medical institution. If a procedure had been established, no questions would arise. Now a lot of different organizations issue documents on gender changes, and not always based on operations that have been carried out, and some change sex based on psychological grounds and also hand out documents," Ozarchuk said.
The General Register Office can not independently judge when someone's sex has been changed, she said.
"We cannot independently solve these issues. It is not within our competence. We simply do not have the right to do this. But this issue must be resolved urgently," she said.