Pope Francis has announced that he will make his first visit to Africa later this year with stops in Uganda and the restive Central African Republic.

"I think it will be towards the end of the year because of the weather," the pontiff said aboard the papal plane as he headed back to Rome after a weeklong visit in Asia, where he drew record crowds.

"The trip has been a bit delayed due to Ebola. It's a great responsibility," he added.  

The Argentinian pope, the first pontiff from Latin America, also confirmed plans to travel to Ecuador, Bolivia and Paraguay in July.

At the same time, the pope has said good Catholics do not have to breed "like rabbits", defending the Church's stance on artificial contraception and appealing to the world's 1.2 billion Roman Catholics to practise responsible parenting.

He said he once asked a mother of seven children who was pregnant with her eighth if she wanted to "leave behind seven young orphans".

"She said, 'I trust in God.' But God gave us the means to be responsible," the pope said.

"Some think, and excuse the term, that to be good Catholics, they must be like rabbits."

Francis said creating new life was "part of the sacrament of marriage".

In Manila, he strongly defended Pope Paul VI's outlawing of artificial contraception for Catholics in 1968.

Following the church's teachings did not mean "Christians should have children one after the other", he said.

His comments came at the end of a trip to the Philippines, the Catholic Church's Asian stronghold, which 2014 passed a family planning law after a 15-year battle by the Church to block state-sanctioned contraception.

The law allows the government to begin distributing free contraceptives to millions of poor Filipinos.

It was a rare loss for the Church, which has for centuries been one of the nation's most powerful institutions and continues to count more than 80 per cent of the nation's 100 million people as Catholics.

Responsible parenthood

The pope said that his predecessor had foreseen the rise in policies restricting childbirth.

"Paul VI was worried by the growth of neo-Malthusianism" (which advocates restricting the number of children the poor can have) which tried to "put a control on humanity... he was a prophet," Pope Francis said.

"The key teaching of the Church is responsible parenthood. And how do we get that? By dialogue. There are marriage groups in the Church, experts and pastors," he added.

In 2013, six months after becoming pope, Francis urged the Church to drop its "obsession" with contraception, divorce, gays and abortion, in an interview signalling a dramatic shift in the Vatican's tone.

The Argentine pope has brought a series of fresh perspectives to the notoriously rigid Church since he took over, signalling a strong reformist drive.

He stressed at the time that the Church's official position had not changed, but said that it should "always keep in mind the individual".

Series of breaks

Francis' papacy — he is the first Jesuit pope and the first from South America — has marked a series of breaks with Vatican tradition.

The pope has become known for his humility and concern for the poor, and has reached out to non-believers and those in other religions.

He regularly picks up the phone to call ordinary people who write to him.

His latest comments are not the first this month to attract attention for their candour.

Last week, when discussing the deadly attack by Islamist gunmen angered by French satirical weekly Charlie Hebdo's depiction of the Prophet Mohammed, the pope said: "If a good friend speaks badly of my mother, he can expect to get punched."