The National Party has received $200,000 from a wealthy Chinese New Zealand couple linked to the businessman behind the foreign bid for the Crafar dairy-farm empire.
The sum is one of a number of large donations to the party's campaign war chest, which has swelled by $355,000 in recent weeks.
Auckland woman Susan Chou donated $150,000 last month on top of $50,000 the month before.
Her husband, Zhaowu Shen, was until recently listed as an adviser to the Chinese Business Roundtable, founded by Jack Chen - the self-described "driving force" behind Natural Dairy NZ, the Hong Kong listed company seeking to buy the Crafar farms.
The Herald understands Ms Chou and her husband - who has business interests in New Zealand, Hong Kong and Vietnam - have also been long-time supporters of National Cabinet minister Pansy Wong.
Mr Shen and Ms Chou have a history of generous philanthropy.
In 2008, they gave $200,000 to fund relief efforts following the Sichuan earthquake and the same year, Mr Shen's company Contue Jinwan Enterprise Group was a major sponsor of the New Zealand Symphony Orchestra's trip to perform at the Beijing Olympics.
The balance of the large donations received by National in recent weeks were $105,000 from upmarket restaurant Antoine's, which is near Prime Minister John Key's Parnell home, and Auckland BMW dealership Team McMillan, which gave $50,000.
Antoine's owner, Tony Astle, has been reported as saying he donated the money because he "loved" Mr Key, who was a longstanding customer at his restaurant.
Team McMillan director Bob McMillan said most of the money donated by his firm was raised during a recent function where Mr Key spoke.
About 180 Team McMillan clients paid "a significant amount" to attend and the firm topped that up to $50,000.
Political parties are required to declare donations of more than $10,000 on the Elections NZ website, which shows the past two months have been good for National.
National Party president Peter Goodfellow said he did not wish to discuss individual donors.
"Clearly we've built our war chest and some of our supporters have been generous," said Mr Goodfellow, who has faced criticism over his fundraising abilities.
"What I've done ... is to get fundraising under way earlier, and as the Labour Party has in the past, we've had some pretty substantial donations."