Health supplement company Blackmores says its chief executive officer has resigned after 18 months in the job.

Richard Henfrey, who has been with the company in a variety of executive roles since April 2009, will remain in the position while the board searches for a new CEO.

The company did not state a reason for his resignation.

Mr Henfrey replaced Christine Holgate, who left to lead Australia Post.

Ms Holgate, once described as Australia’s most important woman, led the company to a huge surge of expansion during her nine years at the helm.

Blackmores shares hit an 18-month low last week after the vitamin maker told investors not to expect an increase in sales to China.

Blackmore shares were down 3.19 per cent, or $3.04, to $92.16 at 1132 AEDT.