timestamp with time zone output incorrect

[Steve Martin <steve(dot)martin(at)nec(dot)co(dot)nz>]

Hi,

We are having trouble with the output of timestamp with time zone with 
versions 8.1.10 and 8.3.1.
It seems reversed, and change over times are incorrect.

timezone for both is:
=> show timezone ;
 TimeZone  
-------------
NZST-12NZDT
(1 row)


Note, change over times for this year is:
Sun Apr 06 02:59:59 NZDT 2008 --> Sun Apr 06 02:00:00 NZST 2008
Sun Sep 28 01:59:59 NZST 2008 --> Sun Sep 28 03:00:00 NZDT 2008


On both versions:
=> select timestamp with time zone '2008-01-01 00:00:00';
     timestamptz      
------------------------
2008-01-01 00:00:00+12

=> select timestamp with time zone '2008-05-01 00:00:00';
     timestamptz      
------------------------
2008-05-01 00:00:00+13
(1 row)


It seems that the time zone off set is reversed.

Also it seems to be using the old change over times.
=> select timestamp with time zone '2008-03-09 01:00:00';
     timestamptz      
------------------------
2008-03-09 01:00:00+12
(1 row)

=> select timestamp with time zone '2008-03-09 03:00:00';
     timestamptz      
------------------------
2008-03-09 03:00:00+13
(1 row)


Checked "postgresql-8.3.1/src/timezone/data/australasia" and the 
information here seems correct.

The date on the system (HPUX 11.23) is correct, e.g.
% date
Thu Apr 24 18:22:42 NZST 2008
% echo $TZ
NZST-12NZDT

The database seems to know we are using the New Zealand  time zone.  It 
seems to think summer is coming  it is winter.

Any ideas anyone?

Thanks
Steve Martin