Pope Francis makes appeal on extremism as he launches Asia tour

Pope Francis appealed on Wednesday for religious unity to counter extremism and intolerance, as the longest tour of the 87-year-old's papacy got into full swing in Muslim-majority Indonesia.

On the first full day of his four-nation trip to the Asia-Pacific, the pontiff zeroed in on the role all faiths can play on flashpoint security issues.

"In order to foster a peaceful and fruitful harmony that ensures peace... the Church desires to strengthen interreligious dialogue," the pope said after meeting President Joko Widodo.

"(Extremists) through the distortion of religion attempt to impose their views by using deception and violence".

Widodo echoed the pope's remarks.

"Freedom and tolerance is what Indonesia together with the Vatican want to spread... in the midst of an increasingly turbulent world," he said.

Indonesia, which is the world's most populous Muslim nation, has long struggled with radical militancy.

Bombings on the resort island of Bali in 2002 that left 202 people dead were the deadliest in Indonesian history and led to a crackdown on militancy.

Catholics represent fewer than three per cent of the population of Indonesia — about eight million people, compared with the 87 per cent, or 242 million, who are Muslim.

But they are one of six officially recognised religions or denominations in the nominally secular nation, including Protestantism, Buddhism, Hinduism and Confucianism.

The trip to Indonesia is the third ever by a pope and the first since John Paul II in 1989.

The pope's fragile health is set to be tested on the trip, which will also take in Papua New Guinea, East Timor and Singapore.

He had not travelled abroad since visiting Marseille in France in September last year.

Accompanying him to Indonesia are his personal doctor and two nurses, but Vatican spokesman Matteo Bruni said that was standard procedure.

The pontiff appeared refreshed when he arrived in Jakarta from Rome on Tuesday, and again when he met Widodo on Wednesday morning in the first major set piece of his tour.

He arrived in a civilian Toyota car, sitting in the front passenger seat before getting out in a wheelchair to greet spectators.

The pope will end his day with a meeting with young people who are part of a global network of schools aimed at helping disadvantaged children, which he established in 2013.