Designer Sally Flannery is one of countless Australian business owners worried about packaging ending up in landfill: and she isn't afraid to ask executives to change things.

"My business is a sustainable business, aiming not to use plastic and all that kind of thing. But about six months ago I was saying, 'Why is shipping so expensive?' " she says.

Entrepreneur Sally Flanney has asked Australia Post to help promote eco-packaging options.

Flannery had been committed to using her own packaging materials when sending her ceramics orders out to her customers. She soon discovered she was paying "at least $300 a month" more to do this because bringing 'bring your own' packaging incurs different fees to Australia Post flat-rate pricing for larger parcels.

A 5 kilogram parcel can cost at least $2 more to send if bringing your own packaging, according to the online postage estimator.