The family of a Perth man missing in the devastating Nepal-Tibet flood disaster zone are still hopeful that he is alive, as more Aussies are confirmed safe one week on from the tragedy.

The number of Australians unaccounted for has been revised down to 38 after five more citizens were confirmed safe, the Department of Foreign Affairs and Trade confirmed on Wednesday morning.

One is in Nepal, one in Tibet, China, and three are outside the disaster zone.

It comes after Sydney woman Cara Severino and another unnamed Aussie were previously located safe in the region.

More than 4,000 people remain unaccounted for in Nepal as the death toll surges past 1,000.

Luke Costanzo's family are among those praying for a miracle after losing contact with him last week.

The 30-year-old West Australian was touring Mount Kailash on the final day of a pilgrimage trek with the non-profit spiritual Isha Foundation when the flood hit.

'It is with heavy hearts that we share our dear son and brother, Luke Costanzo, is one of the Australians still unaccounted for in Nepal following the flooding disaster last week,' a family statement released on Tuesday read.

'Luke is an extremely strong, compassionate, disciplined and spiritual person.

'Once he makes a decision, he commits to it fully, and he was so excited to be visiting Mount Kailash on a pilgrimage trek.'

The family last heard from Mr Costanzo at the Gyirong port border crossing, where the tour group was heading back to Kathmandu on the final day of their journey.

'This is an unimaginably difficult situation for us, and we request the media please respect our privacy during this time,' the family added.

'We truly appreciate all the love and support from friends and family that we've received and ask everyone to keep Luke, and all those affected, in your thoughts and prayers.

'We can do nothing but continue hoping for a miracle that Luke, and the others who remain missing, are found alive and well.

'For those wishing to help in some way—and are in the position to do so—we suggest donating to aid the wonderful people on the ground who continue with rescue efforts.'

Some families have travelled to Nepal to find and identify their missing loved ones.

They include Sydney father-of-two Sriram Parameswaran, who is desperate for news on his wife Shruti Chandrasekaran.

She is among 34 Australians missing from a Himalayan glacier trekking group.

'We have a two-year-old and ten-year-old kids who are waiting in Australia, hoping she is going to come back,' Parameswaran told Nine News.

'I'm here in search of her and hoping as a Father's Day gift I'm going to gift her to my son, that's my plan.'

Cara Severino, 26, was the first Australian to be found and was pictured alongside Australian embassy staff in the Nepal capital Kathmandu on Sunday, after making contact with authorities less than 48 hours prior.

The Wollongong native was hiking through the Himalayas when the devastating flood, triggered by an ice avalanche, struck the region on Wednesday morning, local time.

Ms Severino was near Langtang National Park and survived by forming a group with others who were fleeing the havoc on a tractor.

'Grateful to the crew we formed on that first day when we entered the national park on a tractor,' Ms Severino said in a statement on Sunday.