Antitrust lawyers from the U.S. Department of Justice are still examining the proposal, but the delay is expected to be brief, The Washington Post (NYSE:WPO) reported Saturday.

"The companies have agreed to a brief delay in implementing this agreement to continue our ongoing discussions with the Department of Justice," Google said in a statement. Yahoo officials said, "We have had discussions with regulators and look forward to responding to their questions about this agreement."

The delay will be less than a month, unnamed sources told the Post.

Since the deal was announced in June, critics have weighed in by saying it will amount to a search engine advertising monopoly for the companies, who rank number one and number two in the booming field.