The US Department of Justice (DoJ) wants more time to consider Oracle's $7.4bn Sun deal before giving its approval.
The DoJ has extended the initial review period to resolve issues related to the way Java rights are licensed, according to The Wall Street Journal.
The deadline for the DoJ's initial 30-day review period was set to expire at midnight on Friday.
Despite the delays, the investigation around licensing for Java - a key programming language for Oracle - is not expected to stop the deal from going ahead.
When the deal was announced in April, Oracle said Java is the most important technology it has acquired to date.
The technology underpins Oracle Fusion Middleware, Oracle's fastest growing business.
The DoJ is now expected to approve the deal in time to enable Oracle to complete the acquisition in the current fiscal quarter, which ends on 31 August.