It's over recent Census results, which showed a decline in the number of Welsh speakers.
The Welsh Government say the building remains open to staff and visitors as usual.
Cymdeithas are holding a peaceful protest at one of the entrances at the Welsh Government offices in Cardiff. The main reception remains open as usual to all staff and visitors.
More top news
A cloudy night with drizzle in places. Heavier rain and strengthening winds arriving tomorrow afternoon.
Nazar gave up a career as a property developer to become a humanitarian, raising more than £200,000 for good causes around the world.
Terence Francis was reported missing from his home in Haverfordwest yesterday.