Salaries being paid to the senior staff behind Scotland’s controversial bottle and can recycling scheme have been described by a former SNP government minister as “outrageous”.

David Harris, the chief executive of Circularity Scotland which will administer the Deposit Return Scheme, is being paid £300,000. Executives at the not-for-profit organisation will receive a combined £670,000 in annual salary and fees.

They will introduce and oversee the initiative to boost recycling of empty drink containers. Shoppers will pay an extra 20p for a can or bottle, which will refunded when they return it for recycling.

Industry figures and MSPs – including some on the SNP benches – have been highly critical of the scheme, and two of the SNP leadership candidates, Kate Forbes and Ash Regan, want its August start date to be postponed. Third candidate Humza Yousaf, says small producers should initially be exempt to give them more time to prepare.

SNP MSP and former minister Fergus Ewing has now criticised the salaries being paid to Circularity Scotland’s executives.

“The public will ultimately be the payers for the costs of this scheme, including the salaries of its bosses, with the costs of beverages rising by far more than 20 pence,” he said.

“The payments to the CEO and chair are simply outrageous because the scheme is a disaster and, unless halted, will become a certain catastrophe.

“Calls to halt the scheme are now coming from every sector of business impacted. Circularity Scotland has totally failed to understand how the current system of recycling works and perhaps that is because they failed to listen to — or even meet — those who know most about it. Some major players were not afforded meetings, others did not get replies to requests to meet.”

Lorna Slater, minister for the circular economy, has insisted the DRS will launch in August as planned.

The company is funded by industry rather than government, and ministers say they have no involvement in the recruitment of staff or their pay levels.

Circularity Scotland said: “This information was included in an email to all Circularity Scotland members. We can confirm that as a private, not-for-profit company, we communicate all senior executive salary information to our members and benchmark these against similar post in the industry.

“The deposit return scheme is one of the largest environmental infrastructure schemes ever established in the UK and the executive team have been appointed due to their unrivalled expertise in developing and implementing large-scale projects of this nature.”