A dad taken to Facebook to vent his frustration after Woolworths allegedly ruined his son's specially made frog-themed birthday cake with its "pathetic" decorating.

Shane Hallford, 43, forked out a hefty $50 on the cake to help celebrate Mason's third birthday in Tamworth, NSW.

The dad-of-two said his request for in-store bakers to supply a frog-themed birthday cake was confirmed by the supermarket three days prior to picking it up.

But the police officer and his wife Amy, 29, were horrified to discover that their son's cake looked "nothing" like the treat they had specified.

Instead of the colourful number three and big green frog they had both envisioned, the "mortified" parents were met with a "pathetic" smiley face and small number three clumsily piped in green icing.

The $50 cake created byWoolworths.

Luckily, a sympathetic cake decorator mate came to their rescue, and managed to repair the botched cake just in time for Mason's party.

"I went down to the store three days before my son's birthday to order the cake," he said.

"I explained to them we wanted a frog theme, as my son loves frogs. They told me it could be done, no worries at all.

"He wrote down everything I said and said it would be ready by Sunday morning. I was very excited to see it."

But as he was in a rush on the morning of Mason's birthday party, he didn't actually check it at the store.

A friend came to the rescue and fixed Mason's cake before his birthday party.

"I just assumed it would be fine. When I got