Jamie Fobert's project for an extension to the Tate St Ives has been put on hold for at least a year
The London-based practice has also been asked to re-assess the project after it was suggested that the building may be suited to a different site in the town.
The problems centre on parking - while many residents are keen to see some kind of extension go ahead, most are less keen to lose the 79-space car park that it would occupy.
It is understood that the wider traffic issue is key. Cornwall County Council has told the extension's backers to wait 12 months while an assessment of parking in the town is carried out.
While these decisions might have come as a blow to Fobert, he remains up-beat about his scheme, which would have extended Evans and Shalev's original building.
'We do not mind these problems as there was a lot of support in the town, but there was always opposition because of the parking spaces - it is good that they'll try to sort it out,' he said.
And Fobert also insisted that there was other good news. 'Cornwall has just secured another round of Objective 1 funding from the EU so we can go for that instead of rushing to get the current cash.
'Also we don't need to rush now, which means we can look at the scheme again,' he added. by Ed Dorrell