 <p>After digging on cxf forums, I found the answer.</p> <pre><code>Map&lt;String, String&gt; nsMap = new HashMap&lt;&gt;(); nsMap.put("prefix1", "url1"); nsMap.put("prefix2", "url2"); nsMap.put("prefix3", "url3"); nsMap.put("prefix4", "url4"); nsMap.put("prefix5", "http://www.w3.org/2001/04/xmlenc#"); Client client = ClientProxy.getClient(port); client.getRequestContext().put("soap.env.ns.map", nsMap); </code></pre> <p><strong>I would be appreciated if anyone know on how to do the same for <code>&lt;soap:Header&gt;</code></strong></p>