The decision by the trust, which is located near to the Welsh border, is likely to have a negative impact on thousands of people in Flintshire who have been routinely using it.
“This is a difficult decision that has been taken with great reluctance”
The move to limit referrals from GPs in Wales to the English trust is due to an ongoing funding disagreement.
In a statement, the trust said: “This situation will have no impact on patients who already have an appointment with us and it will not affect our urgent care services, including A&E.
“Any patient living in Wales who presents to A&E will be seen as normal,” added the trust.
Its chief executive, Susan Gilby, said: “Unfortunately, the trust is currently unable to accept any new elective work relating to patients living in Wales.
“We will of course honour any existing appointments so there will be no disruption for patients already waiting,” said Ms Gilby.
“This is a difficult decision that has been taken with great reluctance,” she said. “We are mindful of our position close to the border, with many of our patients and staff coming from both England and Wales.
“Unfortunately, this is a step we have had to take as a result of unresolved funding issues,” she said. “However, contract negotiations are continuing.
She added: “I am grateful to the senior leadership team at Betsi Cadwaladr University Health Board for continuing to work hard in partnership with us to resolve this issue.”
However, a Welsh government spokesman claimed the move by the English acute trust was “unacceptable”.
He said: “Along with NHS Wales representatives, Welsh government has agreed a process of engagement with Department of Health and Social Care officials and representatives from the English NHS to discuss cross-border payment arrangements.
“In the context of ongoing engagement, any actions taken by English providers to limit access for Welsh patients on financial grounds are unacceptable and not in the spirit of reaching a cross-border agreement with English NHS representatives,” he added.