Foreign Minister Julie Bishop said 549 Australians were confirmed as travelling in Nepal, and more than 200 had been accounted for.

"While there are reports of extensive loss of life, at this point there are no reports of Australian deaths," Ms Bishop said.

Two of the Queenslanders missing are Brisbane friends Ben Flanders and Jai Williams, who planned to climb to the Mt Everest base camp,

The Red Cross had listed nine others who are unaccounted for with links to Queensland by early Sunday afternoon.

Mr Flanders mother Trish said he left Australia two weeks ago, with the intention of going on a three-week trip with friends.

Ms Flanders said the enormity of the situation was still sinking in, with the death toll from the earthquake heading towards the 2000-mark.

She said her 25-year-old son Ben, a twin, was physically strong but had embarked on the trip despite recovering from serious chest injuries.

"If I wasn't a spiritual person, I would be frantic….But I'm not crying at the moment and maybe that means he may be alright," Ms Flanders said.

Mr Flanders' friend Jai Williams, a 24-year-old electrician, had recently posted travel photos on Facebook from trips in Indonesia and The Vatican.

The Red Cross listing for Mr Williams says he was planning to travel from Nepalese town of Lukla to the Mt Everest Base Camp. His date of last contact was April 23.

By 12.30pm Sunday, the Red Cross' missing persons list had grown significantly from the morning.

The families of Queensland men Stephen Delahunty, Adam Faichney, Scott Stuart and Karl Townsend also nervously waiting for answers.

Mr Delahunty's wife Terri said the group had arrived at Base Camp but she hadn't heard from her husband after news of the earthquake broke.

"We're sweating bullets at the moment," she said.

"I messaged him and he's out of range, so there's not much more you can do."

Other missing Queenslanders listed by the Red Cross included Adam Jay Murphy, 27; Henk Reece Morgans, 32; Jackson Casagrande, 22; James Scott, 49; Stephen Neary, 48 and Sydney-born Brisbane woman Samantha McGree, 25.

Meanwhile, young Toowoomba adventurer Alyssa Azar is safe at the Mt Everest Base Camp.

Ms Azar, 18, is attempting to become the youngest Australian to scale the world's tallest mountain.

"Alyssa was on a climbing exercise when the earthquake and avalanche occurred," a spokesman for her expedition said.

"She is now at Everest Base Camp awaiting further advice from authorities. Our thoughts are with several others in the climbing party who by Sunday morning remained unaccounted for, as well as everyone else affected by the disaster at Everest and across Nepal."

The Department of Foreign Affairs and Trade has opened an emergency call unit and says Nepal has been hit by disruptions to its telecommunications, transport and tourist infrastructure,

"I urge Australians concerned for the welfare of family and friends in Nepal to attempt to contact them directly," Foreign Minister Julie Bishop said.

She said Australia had pledged $5 million in assistance and would dispatch a disaster response team.

Those unaccounted for from other states include Zachary Sheridan, the younger brother of Packed to the Rafters star Hugh Sheridan, who reached out on social media to people to pray for his sibling.

Another missing man, Sydney's Matthew Graves, posted photographs of the country's intact, picturesque buildings on Saturday.

A day later, his worried family are anxiously waiting for news he is safe following the devastating quake.

"They (parents) are coping as well as they can," his brother Mitch Graves said.

"They are doing what they can with the resources they have to find him.

"It's a bit of a struggle trying to communicate to everyone. It is a waiting game at the moment."

If you are concerned for a relative or friend in Nepal, call the Department of Foreign Affairs and Trade 24-hour consular emergency line on 1300 555 135 within Australia or +61 2 6261 3305 from outside.

- with Rachel Browne