Olaroiu steps in after Juan Ramon Lopez Caro was sacked in the aftermath of November's Gulf Cup final defeat to Qatar.
The Romanian will depart fom his position as manager at Arabian Gulf League outfit Al Ahli, following Saturday's clash with Baniyas - their final fixture before the division takes a break for the continental tournament.
"It was a decision taken by the chairman of the club and I must respect that decision," Olaroiu said after Al Ahli's 2-1 win over 10-man Al Wahda on Monday.
"Ahli haven't had a great season so far, but we are happy to win the three points against Wahda and will hopefully win the next game against Baniyas so they will be in a better position whoever is going to take charge from me.
"My next job is to prepare Saudi Arabia for the Asian Cup, but I won't think on anything else until Ahli's game against Baniyas."
Saudi will contest Group B at the Asian Cup with Uzbekistan, China and North Korea as they look to win the trophy for a fourth time.
