United Nations: The world population will reach 9.3 billion by the middle of this century and 10.1 billion by 2100, and the bulk of this increase will come from "high fertility" countries of Africa and Asia, a UN report said on Wednesday.

According to figures released by the United Nations, India, which is an intermediate fertility country, will see its population peak at 1.7 billion by 2060. China, which is a low fertility country, will see its population peak at 1.4 billion by 2030.

The bulk of the increase will come from "high fertility" countries, which comprise 39 countries in Africa, nine in Asia, six in Oceania and four in Latin America.

High fertility countries will see population growths till the end of the century.

"The future of the population depends very much on what will happen to the future of fertility in the world," Hania Zlotnik, Director, Population Division, Department of Economic and Social Affairs (DESA) told journalists.

"Towards the end of the century low-fertility countries will have a relatively aged population," she said.

"The intermediate fertility countries get more or less to the same point".

Pakistan, Nigeria, the Philippines, Ethiopia, the Democratic Republic of the Congo, the United Republic of Tanzania, Sudan, Kenya, Uganda, Iraq, Afghanistan, Ghana, Yemen, Mozambique and Madagascar account for 75 per cent of the population of high-fertility countries.

The report said that between 2011 and 2100 population in high fertility countries would more than triple, passing from 1.2 billion to 4.2 billion.

During the same period, the population of the intermediate-fertility countries would increase by 26 percent, from 2.8 billion to 3.5 billion, while that of the low-fertility countries would decline by about 20 per cent, from 2.9 billion to 2.4 billion.

The world population is expected to reach 7 billion towards the end of this year.

"What is astounding is that the last two billions have been reached in record time. The population has been adding new billions every 12 years in the last 25 years," Zlotnik told journalists.

"The world hasn't collapsed by adding so many people but what is important is that most of these people are being added in the poorest countries in the world," she said.

The UN official said that if these countries would face "serious problems" in the absence of reduced fertility rates.

Zlotnik said that producing and distributing food for 9.3 billion by the middle of the century were serious challenges.