Metro Manila (CNN Philippines) — Passengers in all four Ninoy Aquino International Airport terminals can look forward to improved security and free intra-terminal transfers soon, the Manila International Airport Authority (MIAA) said Monday.

MIAA general manager Ed Monreal said they are aiming to invite bidders by June to provide and install 2,000 closed circuit television (CCTV) units in the international and domestic terminals.

"We're looking at almost 2,000 units na kailangan i-implement sa buong complex [to be implemented in the whole complex]," Monreal told CNN Philippines' The Source.

"That will cover all the terminals plus the perimeter, plus general aviation," he added.

He made the update following complaints of losses of personal belongings reported by passengers on Ninoy Aquino International Airports' Facebook pages.

Monreal said the terms of reference or TOR, for the proposed bid are being drafted.

"We hope to bid this out as soon as the TOR is completed, hopefully before June," Monreal said.

Monreal also advised passengers to keep their valuables and important documents in their carry-on bags instead of their check-in luggage.

"The bag, once it's entrusted to the airline, wala na ho tayong may hawak doon [it's not under us anymore]," he added.

"But pagka-meron silang reklamo [if they have complaints], they can always call us and we'll help them resolve the issue," he added.

MIAA is also in the process of acquiring new buses that could take care of free transfers for passengers across terminals.

"I hope we'll be able to put that (in place) in the next couple of months," said Monreal. "Wala hong babayaran ang mga pasahero [That's free. Passengers don't need to pay anything]."

The Ninoy Aquino International Airport has figured on the lists of worst airports in the world. Long queues, property losses, power outage, and inconvenient terminal transfers were among the reasons cited.

"We're trying our best to gain some improvements right now, and I hope we're getting there," said Monreal. "Our people are very anxious to prove that we're not that bad after all."

In April 2 last year, when a power outage hit NAIA Terminal 3, the generators were found to have malfunctioned, thus exacerbating the blackout. There were 80 flights cancelled or delayed, and more than 14,000 passengers affected due to the incident.

To avoid a repeat of this, Monreal said that they have working generator sets on standby that are regularly maintained.

The MIAA is taking a step towards a creating more environmentally friendly airports by changing all its lights to more energy-saving LED (light-emitting diode) bulbs, and studying the use of solar power, he added.

"We're trying to refocus ourselves to renewable energy... [Hopefully] we can do it within the next couple of years," he continued. "[Solar power] would be a big ticket project."

"I don't have the figures yet, but that will surely save (a) huge amount," Monreal told CNN after the interview.

"The reckoning will definitely be known by (the) end of this year since it's a rolling implementation," he said, referring to the use of LED lighting. "We need to compare our monthly consumption starting June versus (the) same period last year."

He said that they are also eyeing renovations for Terminal 2, known as the "Centennial Terminal" which handles the flights of flag carrier Philippine Airlines, and the expansion of Terminal 4, known as the "Old Domestic Airport" which services smaller airlines plying domestic routes.