The march, scheduled to take place Saturday, is one of the events in a week of gay pride events called GayFest that began earlier this week. The festival also included debates on gay rights, gay marriage and film screenings.
The Christian group, called the New Right, on Thursday filed a complaint with a Bucharest court to get the march stopped, arguing that it was "a manifestation designed to provoke, obscene and anti-social," the statement said. Authorities said they will rule on the complaint Friday.
It will be the second gay pride march in the former communist country, which decriminalized homosexuality in 2001 to bring its laws in line with EU countries. Romania also passed an act banning discrimination on the basis of sex, age, ethnicity or sexual orientation, the AP reports.
Hundreds of gay rights supporters marched on the streets of Bucharest last year. Police scuffled with a dozen anti-gay demonstrators who had come close to the march, and some were detained.
Earlier this week, gay rights activists launched a campaign to legalize gay marriage, aimed at opening talks with the government on revising marriage laws.