*note: Please include the area code for Tasmania (03) if you calling the Tasmania police from interstate.

POLICE calls for information about the murder of international student Zhang "Tina" Yu have gone unanswered.

Despite a public plea for people to come forward with information about the death of the 26-year-old Chinese woman, whose body was found in the Tyenna River near Mt Field National Park on Tuesday, detectives have not received a single phone call.

Meanwhile, the Department of Immigration confirmed yesterday that it had helped Ms Yu's family in China obtain visas to enter Australia.

They are now believed to be on their way to Tasmania.

Inspector Peter Powell of Hobart CIB said police received calls from several concerned members of the public on Monday evening who provided information which led to the arrest of four people the following day.

Many of those callers did not leave their details, but police are hopeful they may have some further information useful to the investigation and are calling on them to again contact police.

"We haven't had any response as far as anyone calling in," Insp Powell said.

"We would certainly still ask anyone who has got any information to give us a call."

Detectives want to hear from anyone who has any information relating to Ms Yu's death.

They would also like to hear from anyone who heard a disturbance at a block of units at 103 New Town Rd, New Town, last Thursday.

Despite a lack of calls, Insp Powell said he wanted to thank the public for their assistance so far.

He said a New Town woman had stopped a police officer in the street yesterday to provide some useful information. Insp Powell said he hoped more people would come forward.

He said people should not be afraid to approach police with information.

"The people who called us earlier this week tried to help police resolve the case so they are not in any trouble," he said.

"We just want to see if they've got any more details.

"We're certainly not looking to charge anyone."

Anyone with information is urged to contact police on 6230 2111.