The 30-year-old joined the Ligue 1 giants on a free transfer in June after failing to agree a new contract with Liverpool, where he had spent the previous five seasons.
Having been a regular under Mauricio Pochettino at the start of the season, Wijnaldum has since lost his place in the side to Idrissa Gueye.
He has started just half of PSG's 12 matches since arriving and has featured a further five times from the substitutes' bench.
Wijnaldum's tally of 502 minutes is only the 12th most among PSG players in all competitions this term, with Gueye and Ander Herrera featuring more frequently in midfield.
But while having concerns over Wijnaldum's situation at the Parc des Princes, Van Gaal intends to stay loyal to his vice-captain.
"Of course I'm worried," he said at a news conference on Monday ahead of his side's qualifiers against Latvia and Gibraltar over the next week.
"I already talked to him about that when he arrived here. But the alarm bells are not sounding just yet. I have lots of trust in certain players.
"You will remember I took him to the World Cup in 2014 when he was carrying an injury. I started with [Jonathan] De Guzman but Wijnaldum soon took over and did well."
Wijnaldum is suspended for Friday's trip to Latvia as the Netherlands go in search of a third successive victory in Group G.
Van Gaal's side is above Norway on goal difference ahead of the games with Latvia and then Gibraltar three days later.
"This break is a bit calmer. Last time it was almost impossible with three matches," Van Gaal said. "We played those three games with a new group, new manager and new staff.
"I had to convince everyone of my plan, all within one and a half days. We then had one and a half days between each game."