Creating And Dropping Global Temp Tables Inside A Single Procedure

I am writing a procedure that will be called from a java wrapper.

The procedure do a lot of data manipulations and in between i am creating global temp table and saving the data into it for each request thats given as a parameter to the procedure. After all the processing i have to write the data from this global temp table into a physical table and atlast drop the temp table.

Create or replace proc_name ()

update table........

delete from ..........

CREATE GLOBAL TEMPORARY TABLE TSAAG
( supplier_id numeric(10) not null,
supplier_name varchar2(50) not null,
contact_name varchar2(50)
)

insert into............

drop table TSAAG;

End;

creating a global temp table inside a procedure is expensive...

Do we have anything like creating table before and calling the instanse of it in procedure.

Do we have any alternatives to this..