MANILA, Philippines—The Roman Catholic church on Thursday said it has sufficient support in Congress to defeat a controversial family planning bill promoting sex education and the use of contraceptives.

"The bishops are confident they have the numbers," said Maria Fenny Tatad, executive director of the church lobby group Bishops-Legislators Caucus of the Philippines.

Only 99 members of the 238-member House of Representatives have openly said they will support the Reproductive Health Care Act, while the rest are expected to side with the church, Tatad said.

Population control is a highly politicized issue in the Philippines, where more than 80 percent of the 90 million population are Catholics.

The church, which wields considerable public influence, frowns on any artificial form of birth control and has been waging a high-profile campaign to block the passage of the bill, which is now before congress.

International aid agencies and economists have backed the bill saying it is crucial if the Philippines is to curb its annual population growth rate of 2.04 percent, one of Asia's highest.

The bill seeks to establish a national family planning program that would include sex education and advice on birth control, which the church considers "immoral."

Such provisions go against established church doctrine and puts the social fabric of the mainly Catholic Philippines in peril, said Father Melvin Castro, head of the Episcopal Commission on Family and Life.

"We can't simply follow what the world wants us to do," he told reporters.

He said the church was now drafting a parallel bill with the support of some senior members of Congress, a majority of whom are Catholics.

The bill is still in its initial phase, but is expected to include provisions on regulating over-the-counter sales of contraceptives without prescription, as well as controlling the sale of condoms.