The host nation wants to split the event into two rounds with the group stage played in mid-2020 and the final games in 2021.
To make the tournament more exciting and avoid one-sided matches, strong teams Vietnam, Thailand, Australia, and Myanmar will move straight into the final round and not play the group matches.
Vietnam's objection is that if its team fail to beat Australia in a two-legged play-off for a 2020 Tokyo Olympic slot on March 6 and 11, there would be no more matches for the them for rest of the year.
Tran Quoc Tuan, vice president of the Vietnam Football Federation (VFF), said he would protest at the next AFF council meeting in Bali, Indonesia, on March 7 and demand that the event is played in 2020.
If the championship is played over two years, the schedules of domestic leagues and cups would need to be changed to fit around it, he added.
Vietnam claimed the 2019 AFF Women's Championship for the third time last August by defeating Thailand in extra time.
That ended Thailand’s three-year reign as champions.