"Probationers is another term for first year house officers or house surgeons. They are one and the same people,'' he said.
"The use of these titles effectively double counts some doctors and includes other people who are not doctors at all.''
The Government's figures have also been refuted by the senior doctors' union, which last week said district health board (DHB) figures showed only 373 new public hospital specialists had been hired between July 2008 to July 2011.
The union said even that figure was "inflated'' because it included short-term appointments.
Mr Ryall today defended the figures, saying they were conservative.
More than 800 extra doctors had been employed by DHBs compared with 2008, he said.
"Even if you take out the probationers and interns ... there are still more than 800 extra doctors employed by DHBs,'' Mr Ryall said.
"This is an example of the unions getting carried away with half of the story.''
Mr Ryall has also refuted the Nurses Organisation's claim this week that the Government had not hired 2000 extra nurses.
Figures from the DHBs show there were 808.5 more fulltime equivalent doctors in April last year compared with November 2008, of which 2.2 were probationers and interns.
There were 2235.6 more fulltime equivalent nurses over the same period.