Document And Entity Information - shares	9 Months Ended
	Jun. 30, 2020	Sep. 24, 2021
Document Information Line Items
Entity Registrant Name	DEEP WELL OIL & GAS INC
Document Type	10-Q
Current Fiscal Year End Date	--09-30
Entity Common Stock, Shares Outstanding		229,374,605
Amendment Flag	false
Entity Central Index Key	0000869495
Entity Current Reporting Status	No
Entity Filer Category	Non-accelerated Filer
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	false
Entity Ex Transition Period	false
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	0-24012
Entity Incorporation, State or Country Code	NV
Entity Interactive Data Current	No