GPC deputy chairman Dr Richard Vautrey also hit out at 'formulaic questionnaires' on activity incentivised through the QOF for patients with hypertension, warning that many GPs felt this blanket approach was 'intrusive and pointless' and devalued the framework.
Research published in the BMJ on Thursday showed that only 51% of seven-year-olds in the UK achieve recommended levels of physical activity.
Just 38% of girls achieve the level of physical activity recommended by the UK's chief medical officer, compared with 63% of boys.
Researchers found activity levels were lowest among children in Northern Ireland, while children in Scotland were the most active.
GPC deputy chairman Dr Richard Vautrey said GPs were mindful of their role in helping to address obesity in children, and would provide advice when they saw a child who was overweight.
He said: 'Many practices would like the opportunity to refer patients for advice or to gyms or sports centres - the key is having that in place and to enable more access to it.'
Exercise referral schemes were often 'more narrowly based on those who are obese or have medical need', he said, but widening access could be one way the NHS could do more to address rising obesity levels and inactivity.
'Local authorities could look at that with their public health role, particularly if they are reviewing leisure facilities,' Dr Vautrey said. 'They have a health role to play and widening access to facilities could be a way to support that.'
But he criticised use of the QOF to incentivise 'blanket' targeting of patients with hypertension with the General Practice Physical Activity Questionnaire (GPPAQ), warning it devalued the framework.
'We need to get away from formulaic questionnaires. Countless GPs are telling us it is intrusive and pointless.'