Bruce Perens writes (Bug#4195: dpkg-source and new tar package don't mix):
Package: dpkg
Version: 1.3.5
The latest iteration of the tar package unfortunately is not able to
understand the -- flag. I suggest you not use that flag in dpkg-source
for now.
Thanks for pointing out what was wrong.
I have worked around this in 1.3.6 by removing the `--' argument.
However, this will cause dpkg-source to break if the next argument
ever starts with a `-' so I do not propose to leave this workaround in
permanently.
I shall leave this bug report open against dpkg so that I do not
forget to change it.
Ian.