Health officials have denied patients are being misled over prescription medicine changes.

A cheaper medicines push by the federal government, which came into effect from September 1, enabled patients with chronic conditions to receive prescriptions that last 60 days, rather than the previous limit of 30 days.

A Senate estimates hearing on Thursday was told 200,000 60-day prescriptions had been issued in the first month of the new scheme.

Medicines as part of the list of 60-day prescriptions include treatments for heart conditions, osteoporosis and Crohn's disease.

Liberal senator Anne Ruston said pharmacists were being abused by patients because of misunderstandings surrounding the 60-day changes, but health department officials said campaigns had been rolled out explaining the changes.

Pharmacists had concerns over the new dispensing arrangements, claiming the measures threatened their financial viability and dispensing fees.

The hearings were told between May 1 and September 30, there were 48 applications for new pharmacy approvals, of which 18 have already been approved.

There were also four applications for pharmacy licences to be cancelled.

The Pharmacy Guild has started negotiations with the federal government on a new community pharmacy agreement, with talks beginning in September when the dispensing changes came into effect.

Public Service Minister Katy Gallagher said up to six million people would benefit from the prescription changes.

"People will be getting twice the amount of medication for the cost of a single script," she told the hearing.

The health department will spend $6.5 million on an eight-week advertising campaign, which began last month, outlining the changes.

The department revealed it had contracted work to consulting firm McKinsey to provide advice on the policy.

The advice looked at pharmacy models in other countries such as New Zealand and Canada where similar rules were in effect.