temporary table inside procedure oracle

Question

I'm in a situation right now. I'm migrating several procedures from Mysql 5.0 to Oracle 11g. Mysql procedures allow me to:
1. Create temporary tables
2. Insert data into temporary tables / Query these tables / Do some processes
3. Drop temporary tables

I've been searching and found I can not create DDL Statements within procedures without EXECUTE IMMEDIATE statement. I tried to create the temporary table with that statement, and immediately insert some values on it but it does not work 'cause the table does not already exist. I tried to create a function which creates a temporary table, then call it from the procedure but the same happens.

I need to achieve the same steps I'm doing with MySQL. This situation happens very often (there are so many procedures with this kind of "issue") and they are quite large.

What options do I have, what do you recommend ?