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PEOPLE GROUP PROFILE

The Big Sepik of Papua New Guinea

The Big Sepik of Papua New Guinea, numbering approximately 18,500 people, are No Longer Unreached. They are an indigenous ethnic group of Papua New Guinea. They are an Indigenous people, in the New Guinea people cluster of the Pacific Islander Peoples affinity bloc. Their primary religion is Roman Catholicism. They primarily speak Iatmul.

Photo by Google. (2025). Image generated by Gemini 2.5 Flash: Big Sepik

Fast Facts:

Affinity Group: Asian Pacific Rim Peoples
Country: Papua New Guinea
People Cluster: New Guinea
Primary Language(s): Iatmul (ian)
Primary Religion(s): Roman Catholicism
Population: 18,500
Strategic Progress Index (SPI): No Longer Unreached
Global Status of Evangelical Christianity (GSEC): 5% or Greater but Less than 10% Evangelical
People Group ID: PG009782
View on Joshua Project

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Pray for the Big Sepik of Papua New Guinea

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Dig Deeper (Religion):

Primary Religion: Roman Catholicism
Religious Affiliation: Christianity

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Dig Deeper (Language):

Primary Language: Iatmul
Language Family: Ndu

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Media Resources in Iatmul:

Films:

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Provided by the Jesus Film Project

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Bible Resources in Iatmul:

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Provided by Faith Comes by Hearing

Or check out the Iatmul bible resources at Bible.com

Linked from YouVersion

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Next steps for the Big Sepik

The Big Sepik are Unengaged and Unreached, which means there are less than 2% evangelical Christian populations among which there are no known efforts focused on establishing self-sustaining churches consistent with evangelical faith and practice.

Begin signifcant prayer and fasting for this group
Send cross-cultural teams to discover and research this people group
Begin gospel seed sowing and church planting among this group

Next steps for the Big Sepik

The Big Sepik are Engaged yet Unreached, which means there are less than 2% evangelical Christian populations but there are sustained efforts at establishing self-sustaining churches consistent with evangelical faith and practice.

Continue prayer and fasting for this group
Continue gospel seed sowing and church planting among this group
Begin training up local leaders to lead and develop strategies to reach their own people

Next steps for the Big Sepik

The Big Sepik are No Longer Unreached, which means there are more than 2% evangelical Christian populations and there are churches consistent with evangelical faith and practice. There is still more to be done among them.

Empower local believers to begin praying for their own people
Continue gospel seed sowing and church planting among this group
Encourage local leaders to being leading church planting strategy and looking for Unreached and Unengaged groups nearby

Pray specifically for the Big Sepik of Papua New Guinea

And the people of Israel went into the midst of the sea on dry ground, the waters being a wall to them on their right hand and on their left.
readExodus 14:22

Pray that the God who split the sea so that the Israelites might pass through would do another great work among these people, softening the hearts of those who remain lost to the good news and saving them from their sins.

Children, obey your parents in the Lord, for this is right. “Honor your father and mother” (this is the first commandment with a promise).
readEphesians 6:1-2

Pray that God will bring young men and women to faith in Jesus and that the fruit of their faith will be a powerful testimony as they honor their parents.

I will sing of the steadfast love of the Lord, forever; with my mouth I will make known your faithfulness to all generations.
readPsalm 89:1

Pray that as people place their faith in Christ, they will declare and record His faithfulness and love to be passed on from generation to generation.

The times of ignorance God overlooked, but now he commands all people everywhere to repent.
readActs 17:30

Pray that those God sends to cross cultures will boldly and lovingly declare that God commands all people everywhere to repent.

Big Sepik (ROP3 - 101423) reported in the following countries:

To download a comprehensive people group list in spreadsheet form, visit our Research Data page.

Peoplegroups.org relies on updates from the field and other organizations for much of our data, so if you have any updates, please contact us. We use various international naming standards. For a list of these standards and fields, visit our Definitions page.

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