Pope Francis on Sunday championed a "creative" Catholicism in Asia that reflects the region's diversity, and urged countries like China and North Korea to respond by fostering a proper dialogue with the Vatican.

In a speech to Catholic bishops from 22 Asian countries, the pope said the Church had no choice but to adapt when communicating its message across a region of dramatic contrasts.

"On this vast continent, which is home to a great variety of cultures, the Church is called to be versatile and creative," he told the bishops at a martyrs' shrine some 150 kilometres south of Seoul on the penultimate day of a visit to South Korea.

It is the first papal visit for 15 years to Asia -- a region the Vatican sees as having enormous growth potential to offset dwindling numbers in the United States and Europe.

But nearly a dozen Asian countries have no formal ties with the Holy See, including China -- the great elephant in the Vatican's Asian room -- which bars its Catholics from recognising the pope's authority.

In a "spirit of openness", Francis appealed for a fresh start based on mutual respect and cooperation.

"I honestly hope that those countries of your continent with whom the Holy See does not enjoy a full relationship, may not hesitate to further a dialogue for the benefit of all," he told the bishops.

- A beneficial dialogue -

Chinese Catholics number 5.7 million according to official data, and 12 million according to independent sources. They are divided between an official Church dependent on Communist authorities and an "underground" Church loyal to the Vatican.

Beijing and the Vatican have been at loggerheads since China severed ties with the Holy See in 1951.

In March last year, China warned the newly elected Francis against interfering in China's internal affairs, "including under the pretext of religion".

The pope had offered his blessings in a message to China's President Xi Xinping as his plane flew over China on its way to South Korea last week.

But the message never got through, a failure Vatican officials put down to technical issues.

An even more impenetrable country is North Korea, which carried out a series of short range-rocket launches into the sea just as the pope arrived in Seoul for his five-day visit.

Francis will focus on North Korea when he holds a special Korean "peace and reconciliation" mass in Seoul before his departure Monday.

Other Asian countries with no diplomatic ties with the Vatican are Afghanistan, Saudi Arabia, Bhutan, Brunei, Laos, Myanmar, Oman and Vietnam.

South Korea has a thriving and fast-growing Catholic community, but across the region as a whole, Catholics account for only 3.2 percent of the population.

In his speech to the Asian bishops, Francis acknowledged that the communities they tended to were a "small flock" in a "vast expanse of land", but encouraged them to find a way to shrink the cultural and social differences they encountered.

"There can be no authentic dialogue unless we are capable of opening our minds and hearts, in empathy and sincere receptivity, to those with whom we speak," he said.

- Beware fads and gadgets -

In a message that will resonate in South Korea, where consumer technology is a powerful force, the pope also warned of a growing "superficiality", especially among young people.

There is a "tendency to toy with the latest fads, gadgets and distractions, rather than attending to the things that really matter", he said.

"In a culture which glorifies the ephemeral, and offers so many avenues of avoidance and escape, this can present a serious pastoral problem," he added.

On Sunday, the pope baptised the father of one of hundreds of high school students killed in the Sewol ferry disaster in April.

Lee Ho-Jin, 56, who lost his youngest son in the tragedy, was baptised in a simple ceremony at the Vatican embassy in Seoul, choosing Francis as his baptismal name, the pontiff's spokesman said.

Later in the day, the pope was to hold a mass for thousands of young Catholics gathered from around the region for Asian Youth Day.

According to various reports, scores of Chinese Catholics were prevented from travelling to South Korea for the event, and Beijing also warned Chinese priests in attendance not to participate in any event involving the pope.