The National Anti-Corruption Commission has landed its first blow, with a former employee of the Western Sydney Airport charged with allegedly asking for a $200,000 bribe.

The Australian Federal Police arrested the former employee on Wednesday, alleging they had solicited the bribe while negotiating a $5 million contract for services at Western Sydney Airport (WSA), which is still under construction.

Court records named the individual as Sajish Erasery, who has been bailed and will appear before Sydney's Downing Centre Local Court on April 18.

Under New South Wales criminal law, the penalty could be up to seven years in jail.

Commissioner Paul Brereton said the National Anti-Corruption Commission (NACC) had "chosen to publicise the charge to highlight the risk of corruption in high value and complex procurements in the Commonwealth sector."

"The commission acknowledges the timely and proactive actions of WSA in referring the matter to the commission and the AFP," the NACC said in a statement

"WSA's cooperation was a key enabler of the investigation."

There have been convictions in three other cases, which the NACC inherited from one of its predecessors — the Australian Commission for Law Enforcement Integrity (ACLEI).

One of those cases involved Wenfeng Wei, a former Australian Taxation Office employee who was jailed for five years for accepting bribes.

Earlier this week, the NACC revealed it has 15 corruption investigations on the go, and has received more than 2,700 complaints since it started operating on July 1.

More than 2,000 were dismissed, because "they did not involve a Commonwealth public official or did not raise a corruption issue."

Three cases are being considered for charges by the Commonwealth Director of Public Prosecutions.