Aucklanders being forced to sit out of next weekend's Rotorua Marathon have expressed frustration over the compensation options being offered by organisers.

Aucklanders will not be able to compete in the 2020 event, following the Government's latest Covid-19 announcements - with Prime Minister Jacinda Ardern saying Auckland was due to remain at alert level 2.5 until at least September 23 and that further restrictions on gathering sizes would likely still apply following that.

Rotorua Marathon organisers put a statement on social media last night, saying "unfortunately participants residing in the Auckland region will not be able to take part in the 2020 Rotorua Marathon".

"We are extremely disappointed that this is the case but the safety and wellbeing of all participants remains our priority."

All Auckland-based entrants could receive either a 50 percent refund of their entry fee or a free transfer to the 2021 Rotorua Marathon, scheduled to be held on May 1.

The Facebook post has received a number of comments, many from Auckland-based runners upset that a full refund had not been offered.

Aucklander Brie Tawhai, who was set to participate in the race, told the Herald the announcement has been a "hard pill to swallow".

"The 50 percent is a bit of a slap in the face considering the event is still going ahead," she said.

"Of course you appreciate that there are costs but it just seems quite off, they're still getting over 1000 people competing from different regions."

"I don't think I would be as upset about the whole thing if they had offered a 100 percent refund, essentially that's like us saying we want to host a concert in Auckland with major headliners and two weeks before say Bay of Plenty and Southland can't come ... and we're not going to give you all your money back but then still run the concert."

When asked about the refund policy, Athletics New Zealand CEO Peter Pfitzinger told the Herald they wanted to remain consistent with what was offered in May, when the event was initially supposed to go ahead.

Participants were offered the same deal, a 50 percent refund, or entry fee transfer to either next weekend's postponed date or next year's event.

"We're trying to be consistent with what we did so to chop and change didn't feel like the right approach and I do imagine most will just shift it to next May," he said.

"We have been looking at what's happening in the overall events industry ... the different events are offering a transfer or partial refund, it's quite unusual that a full refund is provided."

More than 600 Aucklanders have entered the event - almost a third of the total number of participants. Organisers were working on contacting Auckland-based entrants individually from today.

With participants having declared their address on entry, Pfitzinger was confident policing the rules wouldn't be an issue.

"On registration people put where they're from so we are contacting each of the people who registered from the Auckland region individually, explaining that they're not able to participate in the event and here are the options," he said.

"If people want to be deceitful and lie and cheat, I'm sure they could, but we have their addresses so we know who the Aucklanders are."

With accommodation booked, Tawhai said she and others she had spoken to, still planned on travelling to Rotorua and were under the impression they would be allowed to attend as spectators.

However, Pfitzinger said that wouldn't be the case and Aucklanders needed to abide by level 2.5 restrictions both in and outside of Auckland.

"Aucklanders should behave as if they were taking their restrictions with them and right now the restrictions for Aucklanders is gatherings up to 10," he said.

"Could someone drive and watch it, they could, but they are being asked to bring their restrictions with them when they leave Auckland."