The Netherlands coach turned down several chances to talk about a move to the top Premier League side during a news conference in Hoenderloo, where the Dutch squad is holding a pre-World Cup training camp.
"I'm here as Dutch national team coach, not the future Manchester United coach," Van Gaal said.
"You must wait until the process is complete. If you want to know more, then you must be at Manchester United F.C. or any other club," he added in a testy exchange with reporters.
He also declined to reveal his plans for Wednesday, when there is a day off for the Dutch players at the camp, prompting speculation that it might allow the 62-year-old to fly to England to sign a contract.
"Are you getting on a plane tomorrow" a reporter asked.
"Ask Manchester, I don't know," Van Gaal said. "Now there will be press sitting (outside my) house tomorrow to see what I'm doing.
"I said a few words last week about Manchester United because there were uninvited English journalists here and I thought it would be a little mean spirited if I did not answer a few of their questions.
"I mumbled a few words to them and from that they write 60 full pages. But you can't do anything about it."
On Wednesday last week Van Gaal told English journalists that he "would love" the United job, and that "I hope I shall be the one" chosen as their new manager.
He also aimed a put-down at a BBC reporter who asked him what he knew about Manchester United. "That's a stupid question," said Van Gaal, whose relations with the media are rarely relaxed.
United are looking for a new manager after sacking David Moyes in April. Ryan Giggs took temporary charge of the team for the final four Premier League games of the season, as United finished seventh and missed out on qualification for European competition.