The ministers have been considering the bid for several weeks since the OIO gave its revised recommendation to them.
The revised recommendation will require Milk NZ to spend $2m more than it would have under the January approval.
The new conditions require investment of at least $16 million for additional development by May 31, 2017.
Many of the other conditions are the same, including establishing an on-farm training facility and giving two annual scholarships of $5000 to trainee farmers. It must also provide walking access over Benneydale and Taharua stations, and protect sacred Maori sites, including returning the Te Ruaki pa site to the Crown for nothing if required in a Treaty settlement.
Sir Michael Fay - the leader of a rival bid by a consortium that had challenged the original consent - said the deal set a precedent that would "open the farmgates'' for a flood of other overseas investors.
He said the group was disappointed and its iwi members were "justifiably angry''.
"It is hard to comprehend that this sale can go ahead only because a Government-owned entity, Landcorp, has partnered with Shangahai Pengxin to provide the necessary business acumen and expertise required for OIO approval.
"It would mean any potential foreign owner would be approved if they could 'buy in' sufficient New Zealand expertise to effectively make a nullity of this key requirement in the OIO rules.''
See the Overseas Investment Office's new recommendation here.
See a copy of the OIO's decision summary here.