Dragonish caterpillar from North Vietnam
My comment above is actually likely wrong. 

Instead, I think this is possibly the larva of the rose-myrtle lappet moth (Trabala vishnou) in the Lasiocampidae. (It may also be the larva of the closely-related roseapple caterpillar, Trabala pallida -- see here and here). 

I don't know this group of moths at all, but a series of failed "Lymantriinae" searches and otherwise successful image searches led me to this genus and these species. Lack of reputable resources available in English online make differentiation between species in this genus very difficult for me. Below are some images of Trabala caterpillars:

 

 Images Source: Koh Chang Nature 

You can see a very smilar image to the ones above on flickr.