The Abbott government came up with its pledge to create 1 million jobs in five years solely on the employment growth rate achieved under the former Howard government, a Coalition insider says.

In comments that cast further doubt on the achievability of the pledge made before the election last September, a source has told Fairfax Media that no modelling or detailed calculations were done to reach the figure of 1 million jobs.

Previously said a Coalition government would create a million jobs in its first five years: Prime Minister Tony Abbott. Credit:Andrew Meares

Rather, then opposition leader Tony Abbott's office took the employment growth rate of about 2.2 per cent year-on-year under the Howard government and used it to extrapolate its job creation target.

''Abbott's office assumed they could achieve the same outcome,'' the source said. ''There was no detailed modelling or serious work done to justify the 1 million job target. They looked at the Howard record and said, 'We can match it'.''