She said it was heartbreaking to know there would be family moments that would forever be missed.
"It is time that can never be brought back," she told SBS News.
"They are having a childhood without any grandparents at all at the moment.
"We try and have as many video calls as we can. But you know what kids are like, they are running to and fro. I don't feel like that relationship can ever be built through a video screen."
Ms Johnson is an Australian citizen who has lived in Perth for the past decade with her husband, who runs a small business as a carpenter.
She said not having parental support as she raises her two young children has been tough.
"We certainly expected with Jarrad, my second child, that my in-laws would be over for the birth. We don't really have any other family around us here," she said.
"The last six months, which is how old my baby is, have gone along without me soaking it in.
"It feels like it has not been something to really remember as a positive experience."
Emergency border rules implemented in March 2020 recognise a spouse, de facto partner, dependent child or legal guardian as immediate family for travel exemptions, but parents and grandparents don't qualify.
Earlier this year, a petition with 70,000 signatures was tabled in parliament by independent MP Zali Steggall calling for these exemptions to be changed to allow parents of Australians to enter the country and reunite with their children and grandchildren.
The Australian Border Force has said its current restrictions are necessary to protect people in Australia from COVID-19, enable as many Australians to return home as possible and ease pressure on quarantine systems.
In June the ABF told SBS News there were no plans to include parents in the definition of immediate family for the purpose of travel exemptions.
It grants exemptions on a case by case basis where reasons are “compassionate and compelling”.
“These include, but are not limited to, needing to travel due to the death or critical illness of a close family member,” the spokesperson said, adding that all exemptions are “balanced against the government’s intent in protecting the health of the Australian community”.
But with nearly half (49 per cent) of all Australians either born overseas or with at least one parent born overseas, according to the 2016 census, the policy has a widespread impact.
Source: Facebook/Joanne Johsnon
Ms Johnson said she did not understand the justification for the policy.
"It is very cruel to keep families away from each other. They're not being allowed in, but we're not allowed out without meeting specific requirements - and it would mean having to leave the country for at least three months," she said.
She said that in a Facebook group for families affected by travel restrictions, there were some Australian citizens and permanent residents who were leaving the country for good over the policy.
"I know of people in our community who are going home. They have got their exemption and they have made their plans to go," she said.
"They are taking those well-needed skills that Australia was desperate for originally and they're going. They can't continue over here, without the support of their family.
Source: Facebook/Manav Jaggi
"And a lot of people say, well, you chose to migrate to Australia. You chose to be away from your family.
"But when we did, it was in that knowledge that there was only 24 hours at the most away. It was a plane journey.
"And if someone becomes sick back in the UK, it is not just that simple to jump on a plane and go see them."