"Australia is a multicultural nation that is drawn from a wide range of backgrounds," the newly appointed assistant priest to the Catholic parish of Page and chaplain to the local Korean community, told Fairfax.

"As a country it is trying to make up for the mistakes of the past; to not discriminate against others on the basis of race and to protect nature. I see Australians as enjoying life as true humans."

The 35-year-old, who celebrates his first Australian Christmas mass on Sunday at the St Vincent de Paul church in Aranda, has had a very different experience of Christianity to many of his parishioners.

Catholicism did not reach Korea until the late 18th century and was fiercely opposed by the government of the day.

The nation is rich in martyrs with 103 indigenous saints. A further 124 individuals have been beatified.

In 2014, shortly after returning home from three years serving the Korean Catholic community in Brazil, Father Thomas met Pope Francis at the Shrine of Solmoe, the birthplace of the first Korean to be ordained a priest.

Baptised at the age of 16 in 1836, St Andrew Kim Dae-geon walked to Macau, which took six months, to study Catholicism.

He was martyred by Korea's Joseon government in 1846, only 13 months after his ordination in Shanghai.

Father Thomas said he had struggled to explain the meaning of the Pope's veneration of Korea's martyrs to the Solmoe congregation.

"I said it was because of the martyrs all Koreans had freedom of religion," he said. "Nobody is persecuted for their faith today. 100 years ago that was not the case."

Nineteenth century Korea was governed under a rigidly hierarchical caste system.

"One per cent were the nobility who had everything," he said. "The other 99 per cent were virtually slaves. The church represented a more democratic outlook and the hope of a world in which things were different.

"Our martyrs believed in two heavens. One was created in the real world in the hearts of the congregation. Within the church everyone was treated with equality and dignity.

"The other was the Kingdom of God and the place they knew they would go if they were martyred for their beliefs."

Traditionally dominated by Buddhist and Confucian beliefs, Korea embraced Christianity at a startling pace.

"By the 1990s 50 per cent of the population were Christians," Father Thomas said. "But now half of all Koreans are without a religion. Catholics make up 10 per cent of the population."

As in Australia, Christmas has become a materialist festival.

"It has lost its traditional meaning, becoming a commercial carnival to provoke consumption," he said. "Korean Catholics, though small in number, try to convey Christmas's true meaning through acts of charity."