Using conntrack to delete all connections for one source address

Is there a way of using conntrack to delete all connections
associated with one
particular source address? If I do:

conntrack -D --orig-src 192.168.4.240 -p tcp

I get:

NFNETLINK answers: No such file or directory
Operation failed: such conntrack doesn't exist

However, if I specify all parameters (source and destination
IP and ports) then
it works. Doing it this way makes it quite difficult
deleting all connections
for a particular host.

conntrack v1.00beta1
libnfnetlink-0.0.14
libnetfilter_conntrack-0.0.30

Andy Beverley