Yes, I agree with Ronpakis, it seems to be a Nias knife/dagger called Si euli. The blade form and also the brass handle is typical. BTW, it's a very rare dagger. 

 Is there a sheath as well? 
Sometimes this daggers are called Nias keris because some sheath's remember to keris sheath's.
http://www.vikingsword.com/vb/showth...highlight=nias  
Regards,
Detlef