'do shell script...' over VPN, delayed

I am using an Applescript that contains this ‘do shell script…’:
do shell script "/opt/local/bin/sendemail -f sales@me.com -t buyer@server.com -u ‘Test email’ -m ‘Message test’ "

When connected remotely using VPN it takes about 60 secs to complete.

Using the pure code on Terminal & still connected by VPN, it takes 1 second:
/opt/local/bin/sendemail -f sales@me.com -t buyer@server.com -u ‘Test email’ -m ‘Message test’

Using these emails on a regular basis is therefore crippling our remote taskers. Is there any reason why it would take so long using Applescript & is there a solution?