A promising challenger to the supermarket duopoly has dropped out of the race.

Online grocer Supie has entered voluntary administration- owing an estimated $3 million.

Analyst Nick Hogendijk says the start-up battled from day one.

"The big pressure point will be the significant amount of investment in resources she was going to need to have from day one- it was always going to be difficult against a duopoly that was so well set up, so well-geared."

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