"Australia, which also has serious workforce shortages, does better than us with 1.4 specialists for 1000 people."
Alarmingly, Mr Powell said errors may be made as result of understaffing and the overstretching of staff.
"It's very difficult to quantify, but it is there. Often in Health and Disability Commission reports and in other investigations, it does describe a situation of being under-resourced, of workloads being stretched too far, and it is a common feature."
He said many specialists do not have enough time to do what is required of them.
"To give an example, the Government wants to have doctors involved more in decision making, as part of medical leadership, but in a survey done last year of senior doctors and public hospitals through the University of Otago, only 20 per cent of senior doctors believe have they have sufficient time to participate in activities beyond their own clinic."
New Zealand had "become a medical training ground", he said, with the second highest emigration rate of doctors in the OECD.
"We are increasing training registrars who become the specialists of the future - to become the specialists in other countries. And we should be training more of them to work in New Zealand. We need to invest in a specialist workforce and it has to be around the area of salaries."
Mr Powell said of those going abroad, an "overwhelming majority go to Australia, part of that is proximity, but part of it is their training schemes are identical to ours". There is also more money to be made across the Tasman.
He believed if more investment was made, it would pay for itself.
"When we have more specialists we can do things mush more cost effectively and make savings. If we had the right number of specialists we could actually reduce the number of hospital bed days because patients could be treated in a more timely manner than they are at the moment."
Mr Powell said the union and the DHBs agreed last year on a blueprint to address the issue, but in April the DHBs got "cold feet" and distanced themselves from it.