Shares of CSL (ASX:CSL) fell almost 2% in recent trading on Thursday after Chairman Brian McNamee commented on the Australian government's efforts to avoid US tariffs on pharmaceuticals.

McNamee said that he doesn't think US President Donald Trump's demands are "unreasonable," and urged the government to make Australia's Pharmaceutical Benefits Scheme more efficient, The Australian reported Wednesday.

Australia could speed up the system for approvals and the mechanism for pricing of ­innovative new drugs, but this would "come at a cost," and the country would "need to make a contribution," he said.

Trump warned that the US could impose up to a 200% tariff on pharmaceuticals after a grace period of a year to 18 months.