Children's Commissioner John Angus says the link between beer and rugby is pervasive and is affecting younger and younger children.
Mr Angus told an Alcohol Advisory Council conference on Thursday that he is concerned beer sponsorship of rugby is influencing children.
However, the New Zealand Rugby Union says beer sponsorship is critical to funding its grass roots and junior leagues.
The union says there are not enough large companies in New Zealand to fill the gap if alcohol sponsorship is taken away.
The commissioner's comments come as the Government considers a Law Commission report recommending that alcohol sponsorship of sport be banned.