Longest prefix matching CTE

Have an Oracle "connect by" SQL that looks something like :

select phone, pfx, len, (select info from codes where
pfx = x.pfx) infot
 from (
 select :x phone, to_number(substr( :x, 1, length(:x)-level+1 )) pfx,
length(:x)-level+1 len
   from dual
connect by level <= length(:x)
 order by level
    ) x
   where rownum = 1
   and (select info from codes where pfx = x.pfx) is not null
/



Where codes is essentially a two column table :

create table codes(pfx bigint,info text);

And its contents look like :

61882    Australia - Sydney
61883    Australia - Sydney
61884    Australia - Sydney
61892    Australia - Sydney
61893    Australia - Sydney
61894    Australia - Sydney
6113    Australia - Premium
6118    Australia - Premium
61    Australia - Proper



The goal being to match the longest prefix given a full phone number, e.g.


61234567890  would match "australia proper 61"
whilst
61134567890 would match "Australia premium 6113"
and
61894321010 would match "Australia - Sydney 61893"

I know the answer involves Postgres CTE, but I haven't used CTEs much
yet... let alone in complex queries such as this.

Thanking you all in advance for your kind help.

T