Aki was found guilty in May over the murder of his wife on 26 December 2015, at the Kone Tigers oval.
The former chairman was initially arrested and charged on 6 January 2016 with the wilful murder of Louisa Aki, on 26 December 2015.
He stood trial in the Waigani National Court and was found guilty of murder.
Aki assaulted his wife, who was from the Gulf Province, in full view of the public using a timber while under the influence of alcohol, at the Kone Tigers oval.
She was admitted at the Port Moresby General Hospital two days after the assault but succumbed to her injuries on December 31, 2015.
Aki was arrested on January 6, 2016, and has been in custody since.
Justice George Manuhu, when delivering his sentence against Aki on Monday, said it was impossible to impose a good behaviour bond because a life has been lost, despite his appeal to be given a good behaviour bond.
Aki spent two years, six months in custody awaiting trial. That period will be deducted from the 12 year sentence imposed on Monday.
He will serve the remaining 9 years and five months at Bomana.
(Billy Aki filepic)