Forty student doctors a year could be trained in north Wales if Bangor University worked with medical schools in the south, Plaid Cymru has said.
It comes after Health Secretary Vaughan Gething rejected calls to establish a new medical school in the area.
Plaid health spokesman Rhun ap Iorwerth said a joint medical campus involving Cardiff, Swansea and Bangor could help solve doctor recruitment issues.
The Welsh Government said closer working could achieve those results.
Wales has medical schools in Cardiff and Swansea, but students only train in north Wales when they are on placement.
Plaid Cymru's proposal would see undergraduates study full-time in Bangor.
"It's important that we anchor students in north Wales," Mr ap Iorwerth said.
"By aiming to have more and more undergraduates based here, we can strengthen NHS services across the region.
"We could also develop expertise in rural medicine and train doctors to provide services through Welsh."
He said Plaid Cymru's ultimate aim was to see an independent medical school in Bangor, adding: "Our proposals give us a way forward to achieving the goal of providing strong and sustainable hospital services across north Wales."
The party is not clear how much investment would be needed to develop the existing facilities at Bangor University, where there is already a medical sciences department.
Catrin Elin Owen from Dinas, Gwynedd, and Elen Berry from Denbigh are final year medical students at Cardiff University.
Ms Owen said: "As a student coming from school looking to apply to universities to study medicine, it's quite a daunting task.
"Having an option closer to home would not only have encouraged me to apply for that place, but it would also have given me another option to stay in Wales.
"It would also raise the profile of north Wales as a whole and bring doctors to the area."
Ms Berry said students were more likely to begin their careers where they trained: "We're in the process of choosing a place to work next year.
"We've seen already that more than half of the cohort plan to stay in Cardiff and the surrounding area - not because they're from here, but because they've lived here for five years, they know the hospitals and the doctors.
"That's such a help when we're looking for a job."
Dr Phil White from the British Medical Association's council in Wales said: "There is evidence if you can train medical students in one locality that they do tend to stay."
He said the joint campus could be a long-term solution, but warned: "The main medical staffing issues now are short-term."
Dr White also suggested it would be worth exploring the possibility of co-operating with hospitals in the north west of England.
"There are probably as many Welsh students going from north Wales to Liverpool as there are to Cardiff," he said.
A Welsh government spokesman said: "In July, the health secretary issued a statement about medical education and training in north Wales.
"That statement recognised the need for increased medical education to take place in the area.
"We confirmed our view that a collaborative approach based upon Cardiff, Swansea and Bangor Universities working more closely together can deliver this increase and that all parties have confirmed a willingness to progress this work.
"We gave a commitment to update assembly members in the autumn term and this remains the position."
Prof Keith Lloyd, dean of Swansea University Medical School, said: "We are open to working with others to deliver this on an all Wales basis.
"Many of the issues relating to recruitment, retention and the Welsh language in north Wales apply equally in west Wales."
Cardiff University School of Medicine said it fully recognised "the need to develop the medical workforce for rural, urban and city regions of Wales.
"Our students are currently placed all over Wales to gain the experience with patients and health care provision in these very different localities."