The South Australian government remains tight-lipped about how much an invitation-only concert by superstar Sam Smith in the state's wine region has cost taxpayers.

The English singer performed at an exclusive gig in McLaren Vale on Wednesday, in partnership with the SA Tourism Commission. 

The event, held at the d'Arenberg Cube, was attended by 300 people — but the only way to get in was either by winning tickets or being invited.

A number of well-known Australians attended the event as well as members of the media and a significant presence of social media influencers.

SA's Tourism Minister Zoe Bettison would not disclose how much money taxpayers contributed to the event when asked by the ABC.

"We never reveal that commercial-in-confidence," she said today.

"Obviously it was unique, it was a radio competition, I think there were 300 people at the [d'Arenberg] Cube."

Ms Bettison said the government would "look at that return on investment" from the event, but it is unclear how the success of the event would be measured.

Opposition spokesman for the arts and festivals John Gardiner said the government should be "as open and transparent as is possible".

"I think most South Australian taxpayers would think they have every right to know how much the government was spending on Sam Smith's concert and in fact what they were getting for it," he said.

"Otherwise how can taxpayers make an assessment as to whether we were getting bang for our buck?"

Ms Bettison said the event was one of many tourism investments to rebuild the state's "visitor economy", which she said was at 90 per cent of pre-pandemic levels.

In announcing the gig in November last year, the SA Tourism Commission's website said the partnership with Smith would showcase the state's tourism offerings "to a global audience, broadening the state's appeal to travellers".

"The partnership between the South Australian Tourism Commission (SATC) and Sam Smith will highlight key tourism experiences in the state, focusing on food and drink, wildlife, and Aboriginal cultural tourism," it read.

"Sam will share their South Australian adventures across social media, which has a significant following of over 35 million globally."

The SA Tourism Commission has publicly available guidelines for using social media influencers.

For example, it says it will work with influencers who have an average engagement rate of 3 per cent or more on Instagram.

Smith has posted on social media about their travels, including to Cleland Wildlife Park, while the South Australian Tourism Commission's account posted that the singer went to a restaurant in Port Willunga.