try this

DECLARE
--qryCtx DBMS_XMLGEN.ctxHandle;

type a is ref cursor;
c a;
qryCtx number;
result CLOB;

BEGIN

open c for SELECT * from emp;

qryCtx := dbms_xmlgen.newContext (c);

DBMS_XMLGEN.setRowTag(qryCtx, 'EMPLOYEE');

DBMS_XMLGEN.setMaxRows(qryCtx, 5);

LOOP
result := DBMS_XMLGEN.getXML(qryCtx);
EXIT WHEN
DBMS_XMLGEN.getNumRowsProcessed(qryCtx)=0;
INSERT INTO temp_clob_tab VALUES(result);
END LOOP;

END;

Cheers
Slash