Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2019	Jan. 13, 2020	Mar. 31, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	DEEP WELL OIL & GAS INC
Entity Central Index Key	0000869495
Amendment Flag	false
Current Fiscal Year End Date	--09-30
Document Type	10-K
Document Period End Date	Sep. 30, 2019
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2019
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Well Known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Small Business	true
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock Shares Outstanding		230,574,603
Entity File Number	0-24012
Entity Interactive Data Current	Yes
Entity Incorporation State Country Code	NV
Entity Public Float			$ 2,900,000