A concert promoter is brushing off complaints over the date for a Christchurch fundraiser.

"You are us/Aroha Nui" is bringing artists including Bic Runga and Shapeshifter to Christchurch and Auckland in April in order to raise money to help those affected by the terror attacks. 

However, some Christchurch locals have complained about how their concert will be on a Wednesday night, whereas the Auckland show is on the Saturday before. 

Some have taken to social media to vent their upset.

"A shame that Auckland get the Saturday concert and the city directly affected gets the midweek Wednesday concert how is that fair?" one wrote. 

Another said: "Should be on the Friday in Christchurch the day of the week this tragedy happened and FREE for Christchurch residents. This has affected everybody in Christchurch in one way or another!"

Promoter Mark Kneebone told Newstalk ZB there's a simple reason; they couldn't get the venue on a Saturday. 

He says it's because winter sports matches have already kicked into gear, taking up limited venue space. 

"Wednesday was the best date that we felt we could get. It's school holidays, I don't think a lot of people have realised that yet. We're doing tickets for children as well, as we really want as many people to come as possible." 

Kneebone says there's an amazing response from volunteering artists and the wider community.

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He says he's been inundated with offers from artists, backstage crew, local businesses and others, all wanting to donate their time.

"It's incredible how many acts have come together. This is a bill you'll never see anywhere else. You're never going to see this many acts from so far across the spectrum sharing a stage, so it's completely unique."

The performances are on April 13 in Auckland's Spark Arena, and April 17 at the Christchurch Stadium.