ERROR: COPY delimiter must be a single one-byte character

I want to load the data from a flat file with delimiter "~,~" into a PostgreSQL table. I have tried it as below but looks like there is a restriction for the delimiter. If COPY statement doesn't allow multiple chars for delimiter, is there any alternative to do this?

metadb=# \COPY public.CME_DATA_STAGE_TRANS FROM 'E:\Infor\Outbound_Marketing\7.2.1\EM\metadata\pgtrans.log' WITH      DELIMITER AS '~,~'
ERROR:  COPY delimiter must be a single one-byte character
\copy: ERROR:  COPY delimiter must be a single one-byte character