British-Australian man Danny Flint has to fork out $600 if his family wants to travel back to the United Kingdom again.
The dual citizen, who lives in Brisbane, has been caught off guard by a small but significant change to the entry rules for travellers visiting England, Scotland, Wales or Northern Ireland.
From February 25 this year, the UK's Electronic Travel Authorisation (ETA) scheme will be fully enforced following a grace period.
READ MORE: Trump offered to get 'MAGA Granny' off the hook. She refused
READ MORE: Macca's fights back after council blocks new 24-hour joint on trendy street
An ETA costs just £16 (approx. $A32) and can be used by visitors from 85 visa-exempt countries, including Australia, however dual citizens with Australian and British or Irish citizenship are exempt from needing one.
But there's a catch – these travellers can't use their Australian passport to fly to the UK and won't be let on their flight if their British one has expired.
"I have an elderly parent still in the UK, so [I] do not want any barriers to quick travel," Flint told nine.com.au.
"It doesn't feel fair, and I'm not sure why it has been introduced – definitely another expense, and hassle. Why could an Australian citizen travel on the Australian passport, but a dual citizen couldn't?"
Flint's own British passport has expired, as he had been successfully travelling on his valid Australian passport.
Now, he needs to pay about $600 to renew his and his family's British passports.
It costs about $189 to renew or replace each passport, plus postage fees.
It can also take about 10 weeks for them to arrive in Australia.
The process is so cumbersome that Flint has even considered rescinding his UK citizenship.
Fellow Queenslander Wendy Hilsum was born in the UK and has been using her Australian passport to travel for years too.
"I prefer to just have the one passport," Hilsum said.
"I haven't applied for many years. Australia's passport is the most expensive in the world and it states on there that I am an English-born citizen.
"Not sure why they need that extra money from us."
Hilsum also has elderly parents and doesn't want to be refused travel when she or her sister tries to visit them back home.
"I don't intend to live back in the UK, however my parents are in their 80s so I'd need to be able to travel with ease," she added.
Do you have a story? Contact reporter April Glover at Google Play.