Metro Manila (CNN Philippines, January 23) — Heads up, travelers: the Foreign Affairs department opened 100,000 passport appointment slots for February to May since 1 p.m.

Foreign Affairs Secretary Alan Peter Cayetano added more appointment slots will be opened in the coming days.

The Foreign Affairs Department (DFA) has been implementing reforms regarding passport applications recently, which included a "Passport on Wheels" program.

READ: Roque: DFA improving passport application system

Filipinos lamented the difficulty of securing a schedule in the department's online passport appointment system.

In early January, enraged netizens called on the DFA to fix its system after their website showed the schedule to get a passport was full until March.

Some alleged that "syndicates" who hoard passport appointment schedules to sell at sky-high prices are behind the DFA fiasco.

READ: DFA denies syndicate, opens more passport appointment slots

Cayetano said they are looking into the possibility that alleged syndicates may be using "bots," or software apps doing automated tasks, to make the reservations.

The DFA has tapped the National Bureau of Investigation to look into the alleged existence of syndicates preying on passport applicants by selling appointment slots for as high as P10,000.

Cayetano said he will also ask the Philippine National Police to help in going after the syndicates.

"I'd just like to give a warning to any syndicate – real or imagined – mga sindikato na nagpaplano pa lang o yung mga nanloloko sa Facebook o yung mga actual na nagcha-charge ng 5, 10,000 for passports. We are going after you," the Secretary said.

[Translation: I'd just like to give a warning to any syndicates – real or imagined – those syndicates who are planning or those pulling a fast one on Facebook or those actually charging 5,000, 10,000 for passports. We are going after you.]

CNN Philippines correspondent Xianne Arcangel contributed to this report.