In the latest move to take control of Swiss agrochemicals company Syngenta, ChemChina has raised its bid and proposed a two-step acquisition, international news media report. If successful, the deal would potentially be the biggest-ever purchase by a Chinese company.

Citing people familiar with the matter, Bloomberg said the state-owned Chinese company has offered to buy 70% of Syngenta immediately, with an option to buy the remaining 30%. ChemChina has also offered to buy all of the company at once and has sufficient financing available, the sources added.

ChemChina is seen as offering 470 Swiss francs per share in cash for a 70% stake, valuing Syngenta at $44 billion. The two-step offer would allow ChemChina to integrate the two businesses before assuming complete control. Last month, the Chinese company was said to have bid 449 francs a share, which Syngenta rejected as being too low.

Talks are reportedly advanced, but Syngenta may also be waiting to see if Monsanto will make a counter offer. The US agribusiness giant abandoned its takeover plans in August of this year, after the Swiss company rebuffed a third bid.

Monsanto’s chief operating officer Brett Begemann told reporters last month the company was discussing internally the merits of a new offer for its Swiss rival, as well as opportunities to acquire crop chemical assets from other companies.

A merger with Monsanto would face more regulatory hurdles than a deal with ChemChina which only holds a 5% share of the global market.

Speculation that Syngenta will do a deal has been mounting following this month’s merger between Dow Chemical and DuPont, creating the world’s largest agriculture business. The move could trigger a wave of consolidation in the agrochemicals industry which is under pressure from fierce competition.

Syngenta’s chairman, Michel Demare, told the Swiss newspaper Finanz und Wirtschaft the company is also talking to Monsanto again. "Given what shareholders expect for the next 12 months, going it alone is hardly possible," Demare said. He said the board was considering making an acquisition, merging with a rival or selling the company.

Separately, in an interview with Dow Jones Newswires, Syngenta’s interim CEO, John Ramsay, said the company was prepared to discuss options with the whole industry, including Monsanto; however, “our focus has got to be on the ability to actually believe in the value creation and have the confidence we can pull it off."