Stavros Papadopolous, 21, of New Town, and Daniel Joseph Williams, also 21, from Kingston, were remanded in custody after appearing in the Hobart Magistrate's Court.

Jazmin Iris Haygarth, 18, and John Edward Mollineaux, 43, both of New Town, have been charged with failing to report the killing of a person.

Ms Yu, 26, was reported missing last Thursday and was last seen near Hobart's Mercure Hotel in the early hours of Thursday morning.

She had been studying accountancy at the University of Tasmania in Hobart and was in Australia on a student visa.

Police say Ms Yu's body was found in the Tyenna River, off a track which runs off Gordon River Road, in the Mt Field National Park area about an hour and a half from Hobart.

All four of the accused have been remanded in custody until July 25.