Used in reference to an item, construction or situation of low production quality/effort. For example, poor construction of a house or easily destructible housewares.
Derived from a recurring Australian sketch comedy skit from the 80's starring two brothers, the "Dodgey" brothers, set up to look slightly like a home shopping advertisement, where they would peddle items of poor quality, or shady services.
Person A: "This house doesn't look like it would meet proper Building Regulations..."
Person B: "Yeah, it's a bit Dodgey Bros"