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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 and can also be known as Latmul, Nyaura. They are an Indigenous people, in the New Guinea people cluster of the Pacific Islanders affinity bloc. Their primary religion is Christianity - 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): Christianity - 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

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Pray for the Big Sepik of Papua New Guinea

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Dig Deeper (Religion):

Primary Religion: Christianity - Roman Catholicism
Religious Affiliation: Christianity

%
Christianity - Roman Cath… Adherents

Dig Deeper (Language):

Primary Language: Iatmul
Language Family: Ndu

%
Iatmul Speakers

Media Resources in Iatmul:

Films:

No entries found for: Iatmul(ian). Help build some!

Provided by the Jesus Film Project

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Bible Resources in Iatmul:

Provided by Faith Comes by Hearing

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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

As it is written: “None is righteous, no, not one; no one understands; no one seeks for God".
readRomans 3:10-11

Pray that God will have mercy on those living in broken relationship with Him, and that He will bring many to surrender and repentance at the throne of grace.

And when they saw it, they made known the saying that had been told them concerning this child.
readLuke 2:17

Pray that the lost will receive the good news of salvation in God's Son, have hearts eager to share it with others, and that all who hear will respond with wonder and faith!

Let us then with confidence draw near to the throne of grace, that we may receive mercy and find grace to help in time of need.
readHebrew 4:16

Pray that as people place their faith in Christ, they will boldly draw near to God as they approach Him in prayer, receive His mercy, and find grace for help in their time of need. 

Wash me thoroughly from my iniquity, and cleanse me from my sin!
readPsalm 51:2

Pray that God will raise up believers to go and share the gospel with those in this people group who need to be washed of their iniquity and cleansed from their sins.

Big Sepik reported in the following countries (ROP3):

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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