RPRN Engineering said its mining, oil and gas vacancy index rose by 30%, compared with a 17% increase for engineering and 20% for construction, during Australia's current infrastructure and resources boom.

RPRN Engineering principal Jack Foley said the new figures continued a trend evident in each month since the March Quarter this year.

"We would estimate there are now some 7500 professional engineering vacancies at the moment across the three sectors of engineering, construction and mining, oil and gas," Foley said.

"Some companies have literally scores of unfilled vacancies and in some cases it is beginning to affect their service delivery."

He said another interesting statistic to emerge was a substantial rise in demand for environmental engineers and scientists across all states.

"This demand is reflected in the engineering index as well as in the mining, oil and gas subset," Foley said.

"We would expect to see more modest growth in the next two quarters with the effect of the holiday season and annual maintenance shutdowns being a factor."

Foley said the eastern states were the worst affected shortage areas, with demand for civil engineers in Victoria and NSW up 25%, electrical engineers up 50% in NSW and Queensland and mechanical engineers up 30% overall.

The RPRN Engineering Indices track Internet job advertisements by skill-set and state, to measure problems reported in recruiting sufficient engineering personnel.