Unfortunately in this country, homework is a fact of life. But it doesn't have to be unpleasant - even if it is called work.
The problem is - as the above writers have suggested - when you are having him do it. Immediately after school is the wrong time. He needs to unwind and relax. Probably just before or after dinner should work out fine. Give him his own special place to do it, away from distractions - and sit with him and help him until he is working on his own.
i second that opinion. he's only 5 i assume just past toddlerhood. enjoy your time with him now rather than focus on homework. bonding with him through play will be something he'll remember and love you for all his life.
the above post said it more eloquently but i hope i've made sense.
IMO,
but
I am against homework for Kindergarten, especially when they just start. So my advice would be to quit the "homework" practice altogether (unless it is required by the school which it does not sound like). From my perspective (and that one of my son's teacher) - Kindergarten is about learning to like school, being able to function at school, learning to be in groups and work in groups, cooperation, etc.....
If you insist on practicing reading, try maybe after he has a dinner and had quite a bit of time to relax. If I were you, II would not waste a minute of his (and my) precious time "to wear him down". If you push too hard - he may develop aversion to reading, school, and all. Most 5 year olds are not developmentally ready to read, and there is no need for them to read anyway. By refusing he is trying to tell you something:)
P.S. In a country where I am from you do not start formal schooling till 7 years old and really not required to know letters and numbers. And even then we did not have any homework till later. My mom is a teacher and she claims that now when they require knowledge of letters, numbers, and reading when entering the 1st grade (7 years old), she saw levels on students' knowledge actually dropping by middle school and deteriorating quite a bit by high school compare to my "school years".