<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2006-06-22</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001041514</issuerCik>
        <issuerName>NET 1 UEPS TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>UEPS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001282372</rptOwnerCik>
            <rptOwnerName>GAP COINVESTMENTS  IV LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>GENERAL ATLANTIC SERVICE COMPANY, LLC</rptOwnerStreet1>
            <rptOwnerStreet2>3 PICKWICK PLAZA</rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>90185</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Pursuant to the Stock Purchase Agreement, dated as of June 22, 2006, among General Atlantic Partners 82, L.P., GapStar, LLC, GAP Coinvestments III, LLC, the reporting person, GAP Coinvestments CDA, L.P. and GAPCO GmbH &amp; Co. KG (collectively, the &quot;2006 GA Purchasers&quot;), the 2006 GA Purchasers agreed to purchase an aggregate of 3,000,000 shares of common stock of the issuer from selling stockholders.  Such purchase is expected to be consummated on June 30, 2006, subject to the condition that the representations and warranties of the selling stockholders are true and correct on such date.  If such purchase is consummated, General Atlantic Partners 82, L.P., General Atlantic Partners 80, L.P., GapStar, LLC, GAP Coinvestments III, LLC, the reporting person, GAP Coinvestments CDA, L.P. and GAPCO GmbH &amp; Co. KG will own in excess of 10% of the outstanding shares of common stock of the issuer.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Matthew Nimetz, A Managing Member</signatureName>
        <signatureDate>2006-06-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
