AIR and river searches have failed to locate a missing University of Tasmania international student Natasha Narang.
The 30-year-old Indian national went missing on Friday and police do not suspect suspicious circumstances in her disappearance.
Four Tasmanian Police divers scoured the Tamar River and its banks yesterday after personal items belonging to Mrs Narang were found there on Wednesday.
The Westpac police rescue helicopter was also brought in but failed to sight the student.
Following media reports a motorist has come forward saying she saw Mrs Narang crossing the East Tamar Highway near the Northern Outlet on Friday afternoon.
"We still don't know where she is, we have done a fairly extensive search [in the river] near where the handbag was found," Inspector Darren Hopkins from district support said.
"[A witness] came forward and said she'd seen Mrs Narang cross the highway on Friday afternoon so that helped satisfy us she was alone at the time.
"We will continue to search the Tamar River over the next week or so."
According to police, a builder saw Mrs Narang, who lived at Mowbray with her husband, in the university car park on Friday afternoon.
Shortly after Mrs Narang was seen by the motorist crossing the Northern Outlet heading towards to the riverbank.
Mrs Narang left her northern Indian home in the Sikh community for Tasmania in November 2012 in order to complete a PhD in education at the university.
Police believe Mrs Narang was suffering from study-related stress in the lead-up to her disappearance.
Her sister, Tanisha Wadhwa, said the family was deeply distraught.
Launceston police would like to hear from anyone who may have seen Mrs Narang crossing the Northern Outlet between 1.50pm and 2.30pm on Friday, October 4. Please contact Crime Stoppers on 1800 333 000 or Launceston Police on 6336 3945.
If you need help or counselling, contact Lifelink Samaritans 1300 364 566, Lifeline 131 114 or Beyondblue 1300 224 636.