Simunic was rewarded for leading DPMM to a runners-up finish in the league last year, as well as winning the Singapore League Cup, last month when he was named as Brunei coach for the upcoming 2014 AFC Challenge Cup Group E qualifiers, that will be held in Philippines from March 22 to 26.
Despite now having to juggle his commitments, the Croat insists he will worry about the national team when the times comes, and is fully focused on getting his club side off to the perfect start in the S.League.
"I have more strength and desire now that I'm the national team coach but I'm not thinking about that," he told FOX Sports.
"We have four games [in the league] before I embark on Brunei's Challenge Cup qualification campaign.
"It will be tough playing the likes of Turkmenistan and Philippines, who are now third in Southeast Asia, but I am now only focused on the new S.League season."
Although the Bruneian outfit are expected by many to once again challenge for top honours, Simunic, renowned for being inclined to playing down his side's chances, insists he will be happy with a top-five finish, the same target they set in 2012.
"The management are smart people who understand that, while we don't have many problems, our game isn't fantastic yet and we need time," he added.
"It's not easy to replace all the foreigners in our side. It doesn't mean [Stephane] Auvray can come in and immediately replace [Ivan] Jerkovic, it's the same with [Ivan] Bosnjak and Basiru [Osman].
"But we have good local players on the bench. If everyone plays like they did last year, at the current moment, I think we can battle for a top-five finish.
"It's going to be an interesting season - a lot of clubs have changed their players. Home United are strong, Tampines [Rovers] are strong, even Warriors FC are strong. They've signed big names that are all good players."