Combine peanut butter and honey in a microwave-safe bowl; heat in microwave until melted and smooth, about 30 seconds. Add oats, raspberries, flaxseed and chia seeds; mix well.
Line an 20cm baking dish with greaseproof paper.
Press oat mixture into the prepared dish, using your fingers to flatten into the corners. Refrigerate until set, about 3 hours. Slice into squares or bars.