"There will be a $5000 cash reward for the bag and its contents returned, no questions asked. Also a potential cash reward could be offered for information that may lead to locating the bag."
The writer urged anyone with information to "do the right thing".
"If you would like to make an anonymous tip-off, please contact Crimestoppers on 0800 555 111 with the police case number 200911-9156."
A police spokeswoman said police received a report of items stolen from a vehicle at address on Willis St on Friday last week.
"Items reported to have been stolen include electronics and jewellery. It is said to have occurred between the evening of Thursday 10th and morning of Friday 11th.