You need to take your kitten to the vet. They will tell you what is best for it. Please do not use over the counter "remedies". They are very dangerous and could kill your kitten.
Yes - go to your vet. I use Advantage on mine which is very effective. You don't even need to take your kitten in if you're already registered - you can just pick it up. If your kitten isn't registered yet I'd recommend getting him registered and take him along for a health check. He probably needs worming too and, like flea treatment, you're best using stuff from the vets rather than over the counter.
I had the same problem. I got Dozer at 6 weeks and he was COVERED with fleas. All of the over the counter stuff says not for use on kittens under 12 weeks. I took him to the vet the next day and they gave him a rubdown with some advantage. There were still one or two I could find on him, but they were all gone after 48 hours.
I was told by my vet to use some shampoo we have in the US called De Flea. It is all natural and safe to use on kittens. I do not know if you have it there, but I just used it on my kitten who is a little over 7 weeks old and she is fine. I had wanted to use advantage with my kitten but I was told there is a weight requirement he likes to have and my kitten was too small
Dawn dish soap is a wonder too. I had gotten one of my cats from the street and he was loaded and was only around 4 weeks old. I used Dawn dish soap and a lice comb on him every 3 days and the fleas were gone completely in a week. He got major relief the first time though. We got the ones that hatched from the eggs and broke the cycle in a week. I was not going to try Advantage on him he was sickly from the huge number of fleas. Good luck