The claims were made in London's The Times on Thursday, without any sources cited.
The newspaper reported that redundancy talks had been held with staff over the past days.
The cutbacks were credited to BG's declining output in strife-torn Egypt and falling gas prices for its US shale output.
The flagged "significant" reductions to its reported 1000 workforce in Australia relate to the Queensland Curtis LNG project it operates.
First exports from the $US20.4 billion ($A22.81 billion) project are due in the December quarter.
The project is targeting 8.5 million tonnes per annum and is open to securing more third-party gas.
BG shares plunged more than 15% in a single day during January after it declared force majeure in Egypt and flagged $2.4 billion of Egypt and US-related post tax asset impairments.