Professor Steve Field, a Birmingham GP who will begin the role on Tuesday revealed a no-nonsense approach in his first interview.
He told The Guardian that practices not offering seven-day opening, or that pose a safety risk to patients are at risk of being closed down.
Field said he “would not shy away” from using fines and suspensions of surgery licenses to drive through improvements.
He said: "I will not hesitate at all to order the closure of GP practices that we find to be unsafe, or providing poor access, or which do not care for patients properly or treat them with dignity.”
According to his calculations, at least 10% of the 7,607 (760) practices in England will need to make major improvements.
But Royal College of General Practitioners (RCGP) chair Dr Clare Gerada said Field’s plans are “unrealistic”.
She said: "The concept of widespread weekend access is laudable but quality of care must never be sacrificed for access and GPs are already working 11 hour days, with some making up to 60 patient contacts in a single day.
"No doctor in the NHS should be expected to work weekends on top of this without a break. It is not safe or sustainable, for patients or GPs."
Field said his first act as chief inspector of primary care will be to crack down on England’s out of hours care providers.