By Asif Shahzad

ISLAMABAD (Reuters) - The International Civil Aviation Organization (ICAO) has advised Pakistan to undertake "immediate corrective actions" and suspend the issuance of any new pilot licenses in the wake of a scandal over falsified licenses, according to an official and a document seen by Reuters.

The recommendations from ICAO, a specialized agency of the United Nations that works to ensure safety in international air transport, come days after Pakistan opened a criminal probe into 50 pilots and five civil aviation officials who allegedly helped them falsify credentials to secure pilot licences.

"Pakistan should improve and strengthen its licensing system to ensure that it takes into account all necessary processes and procedures and prevents inconsistencies and malpractices before new licenses are issued and privileges of suspended licenses are re-established," said ICAO, in a previously unreported letter to the Pakistan Civil Aviation Authority (PCAA) last week.

A Pakistani aviation ministry official told Reuters that the country has not issued any new licenses since July, in the wake of the scandal.

The Montreal-based agency's recommendations come ahead of an ICAO audit to assess the country's aviation safety management systems.

The ICAO audit, originally scheduled for November this year, has been moved to June, effectively giving the PCAA more time to work on reforms, the official said.

A PCAA spokesman did not respond to a request for comment.

An ICAO representative declined to comment on specific details, but said in an email that ICAO is "helping Pakistan to recognise concerns, and if they do not take swift action on them we will actively notify other countries about them."

The pilot scandal has tainted Pakistan's aviation industry and hurt flag carrier Pakistan International Airlines (PIA), which has been barred from flying into Europe and the United States.

In addition to revoking the licenses of 50 pilots, Pakistan has also suspended another 32 pilots for a year.

(Reporting by Asif Shahzad in Islamabad; Editing by Euan Rocha and Matthew Lewis)