Local footballers must also receive a medical clearance to return to full contact training and playing.

It follows the strengthening of the AFL and AFLW concussion guidelines in January, when the lay-off period was increased from six days to 12.

"The updated guidelines reflect the AFL's ongoing commitment to the health and safety of all players at each level of the game," AFL general counsel Andrew Dillon said.

"Concussion is a serious issue and we will continue to treat it as such."

Players who show signs of concussion have to be removed from the field of play and assessed and must not return to that match or training session.

After a player is assessed by a medical professional, their return-to-play period includes a period of rest, symptom-limited activity, gradual increase in physical activity and a medical clearance prior to full-contact training.

"The focus must be on ensuring that players pass through each of the steps safely (i.e. rest, recovery and a graded return), without a recurrence of symptoms, rather than simply progressing through a schedule," AFL chief medical officer Peter Harcourt said.

Given the lack of baseline testing at local level, community players may need to work towards a more conservative time line than the mandatory 12-day lay-off period, while children and adolescents tend to require a longer recovery.

The AFL emphasised medical professionals would ultimately determine when a player was ready to return to full-contact training and playing.

The league also announced it had appointed Associate Professor Catherine Willmott as head of concussion innovation and research and Rachel Elliott as head of concussion and healthcare governance.

The pair will "lead development, research, education, innovation and governance" of the league's concussion strategy and work closely with the AFL's game development and football operations departments, along with its 18 clubs.

Australian Associated Press