Vitamins producer Blackmores has reported a 46 per cent plunge in first half profit, and flagged more trouble from the coronavirus.

The Sydney-based business was plagued by regulatory change in China over the period, as well as packaging costs, which resulted in net profit of $18.2 million.

Blackmores earlier this month slashed its full-year profit guidance and announced it was scrapping its interim dividend in a market update.

The company’s revenue was down five per cent to $303 million for the six months to December 31.

Revenue in Australia and New Zealand alone was down 20 per cent to $115 million.

Blackmores said on Tuesday the coronavirus threat and higher costs from manufacturing would have a material impact on its full-year result.

Chief executive Alastair Symington said costs had increased at a greater pace and company structure had become complex.

The executive team will try and simplify these.

Blackmores will also design products for what it called “the modern career woman” in China.

It will also use its manufacturing and partnerships in Indonesia and India to help growth.