HAMBURG, April 26 (Reuters) - Tunisia's state grains agency has purchased around 75,000 tonnes of soft milling wheat to be sourced from optional origins in an international tender which closed on Wednesday, European traders said.

Traders initially estimated the purchase at around 67,000 tonnes.

The wheat was bought in three 25,000-tonne consignments at $173.85 a tonne c&f, $186.73 a tonne c&f and $189.58 a tonne c&f, they said.

The sellers were trading houses Europmarkets, Bunge and Nidera.

Shipment had been sought for June 25 to Aug. 5, varying according to the origin selected.

In its last reported tender on March 31, Tunisia's grains agency purchased around 100,000 tonnes from optional origins.

(Reporting by Michael Hogan, additional reporting by Valerie Parent; Editing by Greg Mahlich) ((michael.j.hogan@thomsonreuters.com; +49 40 419 03 4275; Reuters Messaging: michael.hogan.thomsonreuters.com@reuters.net))