The world population is expected to hit the 7-billion mark on Oct. 31, 2011, according to a report released on Tuesday by the UN Department of Economic and Social Affairs (DESA).

"A world of 7 billion is both a challenge and an opportunity," Babatunde Osotimehin, executive director of the UN Population Fund (UNFPA), said in a statement.

"The population projections underscore the urgent need to provide safe and effective family planning to the 215 million women who lack it. Small variations in fertility -- when multiplied across countries and over time -- make a world of difference," he said.

The planet's population, now almost 7 billion, is expected to reach the 9 billion mark before 2050, according to the revised United Nations projections.

The analysis predicts the world will grow to 8 billion people in 2023, 9 billion by 2041 and then 10 billion at some point after 2081, according to U.N. figures. By the end of the century, Earth will be home to 10.1 billion people, the United Nations said.

Population growth will occur mostly in the so-called "high-fertility countries" in sub-Saharan Africa as well as in Asia, Oceania and Latin America, according to the U.N. figures.

"We must invest the resources to enable women and men to have the means to exercise their human right to determine the number and spacing of their children," said Osotimehin.