Open Door Migration director Jacqui Ure told delegates at the Australasian Oil and Gas conference that there were 151 different types of visa available in Australia.
She warned there were consequences if firms failed to meet the obligations specified by the Department of Immigration and Citizenship.
Employers often have to meet strict training and salary requirements and must display financial competence. And some visas require the employee to display competent English.
A visa must be cancelled within ten days if the employee leaves a company for a new job, and the Department of Immigration and Citizenship must be informed of changes to an employee's role or promotion.
Ure said visas were very strictly monitored, with inspectors able to pay site visits and enter premises without notice, and remove a company's ability to sponsor and cancel visas.
An application form which is filled in incorrectly could also lead to problems further down the line if the applicant wishes to extend their visa, change their status or apply for a new visa entirely.
Delegates heard Perth has now been classed as a regional area for the 857 visa, which Ure described as the "jewel in the crown" of Australia's visas.
When granted, the visa offers permanent residence, has no training requirement and ties the employee into a contract with the sponsoring employer for two years.
Ure said there was a misconception that the visa application process was a relatively simple one.
"You hear a lot about the 457 visa. It's a relatively simple process if you look on the net, but look at the sponsorship obligations," she said.
"It's not about ticking boxes, it's about making sure you can meet the obligations and remain compliant during the three years of the sponsorship or the four years of the visa.
"Companies respond to simplistic classifications that relate to complicated and sophisticated laws.
They don't generally have the knowledge to make a competent assessment of which visa they should select.
"For example, if you look at the direct employee/employer relationship, there are around 15 points you have to make sure you conform to. Most people don't know they exist."
