County officials were urged to refuse the application at a full council meeting in Ruthin on Tuesday.
Lancashire-based developers Acebench Investments bought the 120-acre site at auction in 2002 without having seen it.
Last night, Acebench director Ayub Bhailok said building work should begin next month, and that £100,000 had been released to start the project.
He said: "It has been a very, very difficult and complex period, but we have finally got there.
"We're now looking forward to getting work started within the next month."
No-one from Denbighshire was available for comment last night, although the county is expected to change its recommendation of refusal of the hospital plan before tomorrow's meeting.
