| Cover | Jul. 11, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jul. 11, 2024 |
| Entity File Number | 001-41294 |
| Entity Registrant Name | Onconetix, Inc. |
| Entity Central Index Key | 0001782107 |
| Entity Tax Identification Number | 83-2262816 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 201 E. Fifth Street |
| Entity Address, Address Line Two | Suite 1900 |
| Entity Address, City or Town | Cincinnati |
| Entity Address, State or Province | OH |
| Entity Address, Postal Zip Code | 45202 |
| City Area Code | 513 |
| Local Phone Number | 620-4101 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.00001 per share |
| Trading Symbol | ONCO |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
