Warranties and consumer guarantees are 2 different things - warranties are voluntary, while consumer guarantees are mandatory and apply to all consumer goods sold within Australia from businesses. In other words, I just wanted to clarify that there is no Australian legislation that requires manufacturers to provide 12 month warranties in addition to basic consumer laws.
With regards to warranties on grey imports, they often don't apply even if the item was purchased in Australia - from the ACCC website (note, this actually concerns grey imports purchased within Australia from an importer, not when you are the importer, however the second point that I've bolded is relevant as it means local distributors / manufacturers are not obligated to honour a warranty in this case, so your only recourse would be directly with the original seller, however I do note that they unfortunately appear unwilling to assist) :
Local manufacturers and warranties
If the product comes with a manufacturerโs warranty - that warranty may not apply in Australia, or depending on the terms and conditions may not apply to products sold as parallel imports.
Although your products may carry a particular or popular brand name - if it is sold to you as a parallel import, the local manufacturer is not required to help you if the product develops a fault. You need to contact the seller.
You may not be able to get assistance such as product/technical support or repair/spare part facilities from the local manufacturer or their representative. For example, the software of your product may not be suited for the Australian market. You need to contact the seller.
https://www.accc.gov.au/consumers/sales-delivery/buying-parallel-imports
