Wales is facing a crisis in children’s health, with more young people becoming obese because of sedentary lifestyles, a Welsh assembly committee has warned.

The health, social care and sport committee highlighted that almost 30% of children aged four and five were now obese or overweight – significantly more than the rate in England.

Despite Welsh success in elite sport, such as rugby union and cycling, including Geraint Thomas’s Tour de France win, the committee said the levels of physical activity among children in Wales was among some of the lowest globally.

It expressed concern that fundamental motor skills were not being taught in schools and there was a common misconception that these develop naturally in childhood.

The committee has heard evidence from sports leaders, teachers and politicians during an inquiry into the physical activity of children and young people.

Its Plaid Cymru chair, Dai Lloyd, said: “We have heard perhaps some of the starkest evidence yet that we are facing a national crisis in our children’s health.

“The evidence supporting the need to teach fundamental motor skills at an early age is compelling and there is real concern that vital physical activity is being squeezed out by other priorities in our schools.

“But of course, it’s not just about schools. Physical inactivity is a national problem that affects us all, and requires a cross-departmental commitment from the Welsh government to tackle it.

“If we don’t start taking urgent action now to change attitudes towards physical activity, we are storing up problems for generations to come.”

The committee heard more than 27% of four- and five-year-olds in Wales were overweight or obese, compared with 23% in England.

Dr Nalda Wainwright, the director of the Wales Institute for Physical Literacy, said: “There’s been such a misconception in the world of academia around motor development, suggesting children learn that by themselves through play.

“But that’s like chucking a bag of letters in the room and saying ‘Play with it enough and you’ll learn to read’. We really need to plug this knowledge gap with our teachers.”

The committee made 20 recommendations, including making 120 minutes a week of physical education a minimum statutory requirement, because of concerns Welsh schools were not providing the recommended amount.

A Welsh government spokesperson said it would consider the committee’s recommendations. The spokesperson said the new school curriculum, due to come into effect in 2022, included a focus on health and wellbeing.

“This will reflect the importance of physical activity for our children’s physical and mental wellbeing, supporting their development, and ensuring they grow up to be healthy and confident individuals,” they added.

The Welsh government also recently launched a “Healthy weight: healthy Wales” consultation that outlines the actions to be taken to try to help people in Wales maintain a healthy weight.