The parole board of Israel's Prison Service has granted former Prime Minister Ehud Olmert early release from prison.

Prison Service spokesman Assaf Librati said the board on Thursday granted Olmert's request to reduce a third of his 27-month incarceration sentence.

"As of now, Olmert will be released on Sunday,"Olmert's lawyer Shani Illouz told public radio, noting the justice ministry could still appeal the decision.

The 71-year-old Olmert, who was premier between 2006 and 2009, was convicted of graft and entered prison in February 2016.

His Sunday release would be after he completed two-thirds of his sentence.

Olmert is Israel's first former premier to serve jail time. His imprisonment capped a stunning fall from grace that ended Israel's last serious round of peace efforts with the Palestinians and ushered in the era of Benjamin Netanyahu in 2009.

Olmert won international acclaim for relaunching peace efforts with the Palestinians at the Annapolis conference in the United States in 2007, but they failed to bear fruit and the corruption charges against him have come to define his legacy.