A mum who was so upset by the look of her daughter's 21st birthday cake has taken the cake maker to the Disputes Tribunal.

The cake's major fault?

It lacked marbled blue buttercream filling between the cake layers, the "disappointed" mum said in a refund application made to the Disputes Tribunal.

The woman, who is only named as EL in the recently released decision, said once she ordered the cake she began discussing its design with the cake maker, known as FO, by text.

She specifically asked "for blue marbled buttercream between the cake layers, mini sunflowers and green succulents, macaroons and dried raspberries", tribunal referee K Edwards said in the decision.

"It is agreed a coastal theme was discussed, as was the need for the decorations to be feminine and dainty," Edwards said.

But when mum EL arrived to pick up the cake she was disappointed.

The cake maker offered her a refund, but EL took the cake because it was the day of the 21st celebration and there "were no other cake options at that time".

She said she then had to go and buy more ingredients to improve the cake.

She showed the Disputes Tribunal photos of the improvements she made, including adding gold sugar and a "few extra flowers".

"EL felt the succulents looked more like roses, so she also added a small red flower to the centre to portray a flowering succulent," Edwards said.

Cake maker FO states she made succulents in accordance with photos provided by EL.

"FO copied the green succulents as EL had asked for green. EL states she preferred other succulents in the photos provided, however she did not convey this to FO," Edwards said.

After reviewing the evidence, Edwards said the cake maker delivered the cake they had been requested to make with the exception of the blue marbled filling.

The cake maker agreed she could have communicated the fact marbling could not be achieved in a filling, Edwards said.

"I do not, however, consider that issue justifies a refund being given or that this has devalued the cake in any way," the referee said.

"The filling is the brilliant blue requested and is seen only at the edge, with the eye instead drawn to the decorative icing on the top of the cake."

Edwards said ultimately the failure to provide marbling in the filling was not substantial and did not justify a refund.

The cake maker did, however, offer a refund at the time, and the mum took the cake and chose to ask for a refund at a later date, Edwards said.

"Although I appreciate the difficulty of the situation, in that the cake was collected on the day of the 21st, EL is nevertheless deemed to have accepted the cake by taking possession of it after being offered a refund."

That led Edwards to deem the cake had been made in accordance with the instructions given by EL and so no refund was required.