Group CEO of Aventa (formerly Smith Robertson) James Walker is denying claims of the company having a monopoly on the pharmaceutical industry.

The claim was made by then-opposition senator and now senate president Wade Mark, who said a certain company had a 30 per cent stake in the sector and was abusing its power. He raised the matter on the adjournment of the Senate on January 21.

However, according to the Fair Trading Act, an enterprise is only considered to have monopoly power if it controls at least 40 per cent of a particular market.