Perhaps take the other approach: increase work_mem to make the bulk inserts fit into memory. You can easily undo work_mem changes. It only requires a sighup: reload, not restart.
What memory do you have now and what is work_mem currently set to? Also, have many concurrent, active connections do you average at a time?
thanks - checked with the devs and it does look like the application is doing some sort of a bulk insert, and at the moment it cannot be changed to use "COPY FROM".
will limiting bulk inserts to match the work_mem(assuming this is the guc that is used in this case) reduce this disk activity?