KUALA LUMPUR, May 12 — The National Audit Department refuted today accusations that its investigation into 1Malaysia Development Berhad (1MDB) is been taking too long to complete, stressing that the matter was a top priority.

In a statement, Auditor-General Tan Sri Ambrin Buang said that the department was doing its best to complete its investigation into 1MDB's accounts as soon as possible, and that its preliminary findings would be ready by next month.

"The JAN (National Audit Department) plans to present the interim report of the audit to the Public Accounts' Committee (PAC) the latest by the end of June," the statement read.

"JAN is giving this task a priority," he added.

The Auditor-General has said that his department will call up any individual necessary, even Najib himself, in completing an independent audit on strategic fund 1MDB.

But the PAC has begun its own investigation into the debt-laden state investment firm's accounts, saying that it can no longer afford to wait for the results of the federal audit by the Auditor General.

Earlier this year, Najib ordered the Auditor-General to conduct an independent check on 1MDB’s accounts and prepare a report for further examination by the PAC.

The state-owned firm has also said that it will comply with the audit.

Defence Minister Datuk Seri Hishammuddin Hussein had earlier suggested that an independent international audit firm be appointed to conduct a forensic check on 1MDB’s financials, following the latest controversy over its land sale to Tabung Haji Malaysia.