Try Wavesailing up at camel rock. I think it's cross-on Ne Seabreeze Wavesailing. You need to drive north out of town a few minutes. It's a popular surfing spot.
If you want flat water, consider Coila Lake, about 1 hour north from Bermagui. Access from the Tuross Heads road.
If you're after waves, Merimbula, about 1 hour south. 
Both these places work well in a NE, which is what you'll have at Christmas.
The Bermagui area gets strong consistent NE seabreezes over summer. Ive been amazed at how strong it gets regularly.
As Long Reef suggests the beach south of Camel Rock (Wallaga Lake) looks good, can get heavy with NE swell, but a long beach that can get great waves and clean wind.
Wallaga Lake entrance is closed at the moment, so flat water sailing near the entrance could be ok. Or in the waves just near where the entrance is looks pretty good.
I've seen the odd kiter sailing near the breakwall to Bermagui harbour heading across, but would be almost onshore in NE wind and some rocky little beaches.
I'd agree that some trips to Merimbula would be good, but Bermagui and Camel Rock could be fun.
Cheers
Andy
Hey. Sailed Walaga Lake yesterday - great flat water sailing. I regularly sail off Beauty Point there - works well in a Nor Easterly. You have to drive through the park and there's a little track down to the water. Happy to chat to give better directions.
Im also getting into some smaller wave sailing so keen to have a sail around here (Bermi) if you're keen.
