MACLOCK is one way to do it but it has a lot of other effects that you may be after....and in the end it does not actually block any MAC addresses. The way I have handled this is to create a "Black Hole" VLAN -- in my case I use 999 -- to nowhere and then create MAC-to-VLAN associations on the switch stack. This way, whenever a device with a banned MAC connects, it's associated with a VLAN that has no routing, no DHCP, etc.
Here's the config:
set vlan create 999
set vlan name "BLACK HOLE"
set vlan dynamicegress 999 enable
set vlan association mac 00112233445566 999 <--repeat this for each banned MAC, where of course I'm using 00112233445566 as the example
Hope this helps.