populate value of column

I have a table

CREATE TABLE meter
(
meter_id integer NOT NULL,
area_no integer NOT NULL,
CONSTRAINT meter_pkey PRIMARY KEY (meter_id)
) ;

INSERT INTO meter(meter_id, no_of_bays) VALUES (1001, 4);
INSERT INTO meter(meter_id, no_of_bays) VALUES (1012, 6);

select meter_id, area_no from meter;

meter_id | no_of_bays
----------+------------
1001 | 4
1012 | 6

How can I generate the following result?

meter_id | bay
----------+------------
1001 | 01
1001 | 02
1001 | 03
1001 | 04
1012 | 01
1012 | 02
1012 | 03
1012 | 04
1012 | 05
1012 | 06