The AFL has moved to ban contact training at full group sessions for the next four weeks as the fallout to Conor McKenna's positive COVID-19 test continues.

It means full-scale match simulations at training will cease, however tacking will still be permitted in sessions with groups of up to nine players.

Clubs will be allowed to train with their full group once a week but only on no-contact skills, ball movement and tactic drills.

Additionally, players and approved club staff must not visit other houses, or have visitors in their house, in the period commencing 48 hours prior to their weekly pre-match day PCR test until after that test.

Clubs were informed of the new guidelines on Monday afternoon.

The shift comes after McKenna returned a 'low level' irregular reading on a COVID-19 test taken last Friday afternoon after completing the weekly full contact session with teammates that same morning. 

On the same day the AFL eased restrictions on players to begin activities such as surfing and golf last week, clubs were told small training groups of players were allowed to increase from eight to nine.

However, some clubs spoken to by AFL.com.au said they kept their group training sessions to eight players to minimise the risk.

As of Monday morning, Essendon and the AFL were awaiting feedback from the Department of Health and Human Services as to which players would need to, like McKenna, isolate for 14 days after coming into contact with their teammate.

AFL players are required to complete two COVID-19 tests per week – one at least 24 hours before their full-group training session and one at least 24 hours same before a match.

McKenna's test on Wednesday, to clear him for training on Friday morning, returned negative. However, the test taken on Friday afternoon, to clear him for the Sunday match, returned an irregularity.

After arriving at training on Saturday for his captain's run in his group of 8-9 players, McKenna was informed of the irregularity. He was then sent for an immediate follow-up test which confirmed a positive reading for COVID-19.

As a result, Essendon's clash with Melbourne on Sunday at the MCG was postponed and is expected to be made up at a later date in the season.

AFL general counsel Andrew Dillon said on Sunday the Bombers would still be forced to play their scheduled round four match against Carlton on Saturday night, even if McKenna's small training group of 8-9 players is required to isolate.