The average waiting time for non-emergency surgery in Wiltshire has gone up by five weeks.
An NHS Wiltshire spokeswoman said the previous average wait of 13 weeks had risen to 18 weeks, the national target set by the government.
She said it had seemed there would be an overspend in the budget, and there had been an increase in patients needing emergency operations.
The times will remain until the budget is back to the forecast, she added.
The spokeswoman said: "NHS Wiltshire has therefore asked our GPs to minimise the number of elective, non-emergency surgeries into our major NHS hospitals.
"This does not mean that people will not get treated, and no one requiring urgent medical treatment is affected - all Wiltshire patients who need to have surgery receive their treatment."