Beilharz, from country Victoria, reached the North Pole from Ward Hunt Island, the most northern tip of Canada, at 2.30am (AEST) on Monday, together with husband Rob Rigato, 58, and Canadian Sarah McNair-Landry, 23.
Ms Beilharz's mother Vyrna, 75, of Carlton, was excited and relieved at the news the group had reached the Pole.
"They've done it! It was a huge effort, anything could have gone wrong right up to the last few yards," she said.
"It was never certain that they would make it safely."
The trio started their last push in whiteout conditions that cleared as the day wore on and they trudged through fresh, soft snow.
Since setting out on February 28, they have covered 780km in 55 days, battling blizzards and ice drifts and rafting across open water.
Blizzard conditions
They are catching up on missed sleep at the North Pole and will be picked up by a helicopter and taken to the Russian Barneo Ice Station, then on to Svalbard, which is an archipelago in the Arctic.
Australian expedition co-ordinator Rik Head said ice movement following a blizzard several days ago helped the trio in their final push.
"Last week they were being pushed backwards because of the movement of the ice and in the last day or so, because the blizzard came in from the south, it's actually pushing the ice north again," he said.
Their routine was to trek for 10 hours, sleep for two, then head out again.
They recently quickened their pace from 10 nautical miles to 13 or 14 (from 18.5km to 24 or 26) a day in order to meet the April 26 deadline for their flight out of the ice station.
Vyrna Beilharz said her daughter did not get her adventurous streak from her.
Determined, resilient
"We've always been a family who went for camping holidays and climbed up the odd little mountain in Victoria but that's all," she said.
"She was always very determined and resilient."
Linda Beilharz's son, software developer Michael, 28, said it wasn't unusual for his parents to be trekking across ice caps.
"I know it's not normal but it doesn't seem particularly odd to me," he said.
During the North Pole trek, temperatures dipped to the minus low 30s.
"The thing with the North Pole is you are being moved sideways or backwards or forwards depending on which way the ice is moving at the time," Mr Head said.
Birthdays on ice
"At one stage there overnight they went back three nautical miles (5.5km) so that from that perspective they had to do a lot more kilometres to achieve the Pole than what it would appear on paper."
Food and supplies were dropped to the group by parachute on March 22 and April 10.
Mr Rigato and Ms Beilharz had their birthdays on the ice, celebrating with a special soup and a piece of chocolate.
The pair completed a 35-day crossing of the Greenland Icecap in April 2007. They attempted to traverse the Patagonia Icecap in 2009 but had to turn back due to warm weather.
Ms Beilharz, of Bendigo, became the first Australian woman to ski 1,100km from the edge of the Antarctic to the South Pole in December 2004.
She and her husband are scheduled to arrive back in Melbourne from London on May 6.
