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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

Join others around the world in praying for the lost to be saved, the gospel to advance, the global Church to grow, and for laborers to be sent out and sustained in the harvest.

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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

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

The LORD has heard my plea; the LORD accepts my prayer.
readPsalm 6:9

Pray that lost people will hear the gospel and place their faith in Christ, knowing that He hears their plea and accepts their prayer.

And this commandment we have from him: whoever loves God must also love his brother.
read1 John 4:21

Pray that the good news of God's love will reach everyone in this people group, and that His love will compel them to love others as Christ has loved us.

And when they had prayed, the place in which they were gathered together was shaken, and they were all filled with the Holy Spirit and continued to speak the word of God with boldness.
readActs 4:31

Pray that as people place their faith in Christ, they will be filled with the Holy Spirit and speak God's Word with boldness, sharing the love of Jesus with those around them.

And through him to reconcile to himself all things, whether on earth or in heaven, making peace by the blood of his cross.
readColossians 1:20

As believers cross cultures to tell others about Jesus, praise God for allowing them to be a part of His reconciling all things to Himself, asking Him to help them remember their role in His beautiful plan of salvation for others.

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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