The first of these websites produces a "True Food Shopping Guide" - a list of brands for Australia-New Zealand that are likely to contain or not to contain GE ingredients.
The food labelling standards are, in my view, of little help. In Australia and New Zealand at least, there are too many exemptions from legally requiring labelling. So as a general rule, I watch out for the 'biggies' in the ingredient list of any food I buy: Canola, Soy and Corn. For any food with these ingredients I only buy certified organic products that are GM free (I don't buy Canola in any form or any product at all - it's machine oil, linked to macular degeneration, and in my view is worthy of being made into biodiesel).
You will need to be aware of the likely crop-source of some ingredients. Thickeners and glucose syrup may be derived from corn.
You may need to decide whether you want to buy meat and animal products where the animals may have been fed canola, soy and cottonseed meal. Many people believe those products present as many health risks as the crop/crop-products themselves, and the arguments are presented on the websites above.
Welcome to the ranks of those who squint at ingredient lists!
• Heinz Foods