Some of MMG's chief sales roles, including its head of marketing, will be among those moved from Melbourne to the Chinese capital, placing them much closer to major customers.
A source familiar with the relocation, speaking on condition of anonymity, said there would be a marketing handover to the new Beijing team later in the year.
"The Beijing office will host several functions and is an extension of our head office, which will remain in Melbourne," an MMG spokeswoman said by email, adding it would "improve efficiencies and access to key stakeholders in China".
The Minmetals employees are moving from the group's nonferrous metals unit - and MMG's major shareholder - China Minmetals Non-ferrous Metals Co Ltd, whose premises in Beijing will house the new operation.
MMG operates the giant Las Bambas copper mine in Peru and the Kinsevere copper project in Democratic Republic of Congo. It also produces copper, lead and zinc in Australia.
As well as around 20 transfers from Minmetals, a further 20 will be recruited locally for the MMG Beijing office, the spokeswoman said, adding the copper marketing team would be based in China and the zinc team will remain in Australia.
A Minmetals spokesman said he was unaware of the move.
It was not immediately clear how many MMG staff would transfer from Australia to China or how many Melbourne-based roles would be cut.
A second source familiar with the plans estimated less than 10 MMG staff would move to Beijing. Other positions being filled by Minmetals employees are accounting roles, he added.
The MMG spokeswoman did not provide a figure for head-office staff reductions.
By Tom Daly