It's where the couple first met for a date and both see it as a special place in their relationship.

But the couple is now looking for an alternative venue after fees quietly introduced by the National Capital Authority priced them off the island.

The authority introduced fees in July for venues and parks, which make event organisers pay $50 to book small events of fewer than 50 people and then pay venue fees by the square metre for larger events at Aspen Island, Commonwealth Park and the gardens at Old Parliament House.

Ms Andison received a quote for $1137.49 to hire Aspen Island for a 30-minute wedding ceremony. Zone C on the island is 5687.45 square metres and is charged at 20 cents a square metre each day of the event. Commercial events cost 50 cents a square metre each day.

Event organisers are only able to book sites for the day, rather than for several hours.

Ms Andison said she only found out about the new fee structure when she contacted the authority to book Aspen Island in October. The website did not explain the square metre-based charge, she said.

"It was really quite a struggle to deal with [the authority], really quite frustrating just trying to book somewhere," she said. "I had to chase them multiple times to email me back, call me back."

Working on a limited budget, it was overwhelming trying to find another appropriate venue for 100 guests, Ms Andison said.

Wedding celebrant Steven Murray said the authority's charges would hurt Canberra's wedding economy.

"The ACT benefits massively by having weddings here. For the NCA to all of a sudden to start charging these crazy sorts of fees, it's not really helping the industry, like all the hotels, restaurants and other providers," he said. "It's sort of a disincentive."

Gina Callan, who has been a wedding celebrant for 10 years, said none of her previous clients had paid fees to book the Old Parliament House gardens or Aspen Island, even in cases with more than 100 guests.

Another celebrant, Judy Zilber, said she found out by accident about the fees and that wedding organisers previously paid $25 to unlock the gate at Aspen Island and access electricity.

A spokesman for the authority said fees had not been consistently applied in the past and a review in 2017 formed the basis of the new fee structure, on which the authority welcomed feedback.

Event charges were introduced in 2009 but small events, which were free to book, now paid an administration fee to prevent organisers making several bookings to reserve more venues than they needed, he said.

The fee structure would be reviewed next year, the spokesman said.

"Demand has remained consistent following the charges implemented in July this year," the authority spokesman said.

Mr Murray said he would advise couples to use free locations. Parks managed by the ACT government - such as Nara Park, Weston Park and Glebe Park - offer free event permits but charge a fee for gate access and power use.

But Felicity and Joleneare still looking for another place they can make special.