Scottish Labour, which will enter the campaign as firm favourites, will select its candidate on Sunday, followed by the SNP a day later.
The Liberal Democrats, which held the seat before Walker's election victory in 2011, are also expected to name their hopeful next week.
Holyrood's Presiding Officer, Tricia Marwick, yesterday announced the by-election will be held on October 24 following discussions with Fife's returning officer and party bosses. A council by-election is also taking place on the same day.
The Holyrood contest will be seen as an electoral test of strength less than a year out from the independence referendum.
However the circumstances of the poll, after Walker's conviction on 23 counts of assault on three ex-wives and a step-daughter, have made Labour clear favourites.
Walker was elected as an SNP MSP in the party's landslide 2011 election victory but was thrown out of the party after the domestic abuse allegations came to light, serving as an Independent until his resignation at the weekend.
The SNP has come under intense pressure since his conviction to explain how he was selected to stand for Holyrood despite warnings about his behaviour.
Scots bookmaker McBookie this week installed Labour as 1/2 odds on favourites, followed by the SNP on 6/4, the LibDems on 10/1 and the Tories on 200/1.
Labour will draw up a shortlist on Friday before local party members meet to choose their candidate on Sunday.
Two local councillors, Lesley Laird and Cara Hilton, are expected to throw their hats in the ring along with Fiona Eadie, a procurator fiscal and the daughter of Labour MSP Helen Eadie.
It's understood that Jim Leishman, the former Dunfermline Athletic manager, may also put his name forward. A friend of former PM Gordon Brown, he became a councillor last year and was immediately made provost of Fife.
Shirley Anne Somerville, the former SNP MSP, is expected to seek the Nationalist nomination. Now working as the communities director of Yes Scotland, the pro-independence campaign, she lives in the constituency at North Queensferry.
An SNP spokeswoman said yesterday: "We welcome the Presiding Officer's decision - it is right that the people of Dunfermline can now elect a new MSP at the earliest opportunity."
Scots LibDem leader and regional MSP Willie Rennie, who took the equivalent Westminster seat of Dunfermline and West Fife from Labour in a spectacular by-election victory in 2006, has ruled himself out of the running, a decision that has been taken as a sign his party is not confident of winning.
The old Dunfermline West Holyrood seat was won by Labour's Scott Barrie in 1999 and 2003 but he lost it to LibDem Jim Tolson in 2003.
Walker, then a Fife councillor, beat Labour's Alex Rowley - who has since become the leader of Fife Council - by 590 votes to win the redrawn Dunfermline seat in 2011, pushing Mr Tolson into a distant third place.
The by-election date was set a day after Holyrood voted to dock the pay of MSPs who are jailed.