Installing OpenVAS on Mac: openvas-nvt-sync does not see md5sum

I am installing OpenVAS on my MacBook Pro 10.10.1 using MacPorts.

I got to the step of downloading the test database:

$ sudo openvas-nvt-sync

The command gave the following output with error

OpenVAS NVT Sync $

Configured NVT Feed: rsync://rsync.openvas.org:/nvt-feed
Synchronized into: /opt/local/lib/openvas/plugins

Searching for required system tools ...
Error: MD5SUM not found

I then installed coreutils via Macports

$ sudo port install coreutils

and added the following to my path

/opt/local/libexec/gnubin

the command which md5sum returns the correct path

$ which md5sum
/opt/local/libexec/gnubin/md5sum

I then ran openvas-nvt-sync again with no success. I even tried adding the path to /etc/profile as I thought it might be a user based issue.

Additionally, looking at the openvas-nvt-sync source code, I can see that it does use the output of which md5sum as the test for md5sum being available on the system.

Any ideas? Thanks!