The Department of Health in the Philippines has said it will investigate the actions of four milk formula companies, after the Guardian exposed the illegal and clandestine methods used to market products to mothers.

Officials in the DOH confirmed they had called an emergency meeting and had also passed on the violations uncovered by the Guardian to the Food and Drug Authority, which holds the power to formally investigate and hand out financial punishment.

Representatives from Nestlé, Abbott, Mead Johnson and Wyeth (now owned by Nestlé) were described as a constant presence in hospitals in the Philippines, where only 34% of mothers exclusively breastfeed in the first six months of their child’s life.

The representatives reportedly hand out “infant nutrition” pamphlets to mothers, which appear to be medical advice but in fact recommend specific formula brands and sometimes have money-off coupons.

They were also found to be offering doctors, midwives and local health workers free gifts and sponsored trips paid for by milk formula companies, to win their loyalty. This is a clear violation of Philippine law. All four companies have rejected the allegations and denied any wrongdoing.

Dr Anthony Calibo, the national programme manager for infant and young feeding, and division chief for the children’s health division of the DOH, said he was “aghast with the rampant violations that this investigation shows are still happening”.

“It has been a struggle for government to crack down on all of these illicit practices of the milk companies but we thought that things had changed a bit and improved,” said Calibo, who said the DOH was now reaching out to their offices at local level to “investigate and validate these clear violations”.

“We will also be making sure the FDA looks into the matter because they are the regulatory body with the power to implement sanctions, such as fines,” Calibo added. He admitted that a lack of resources meant the DOH struggled to regulate the activities of milk formula companies and gathering evidence of violations was equally tough.

Working with Save the Children, the Guardian compiled reports from doctors, nurses, midwives and mothers which demonstrated ways in which the milk formula companies were either breaking the law, or using loopholes, to promote milk formula to mothers.

As a result, many women were found to be spending up to three-quarters of their income on formula for their babies, sometimes denying themselves food to afford it. Some were living without running water and electricity, causing problems when trying to sterilise bottles.

Nestlé, Abbott, Wyeth and Mead Johnson were found to be offering doctors, midwives and other health workers meals, cinema and theatre tickets and gambling chips, as well as all-expenses-paid sponsorship for attendance at lavish medical conferences. This is a clear violation of Philippine law.

In statements to the Guardian made after the investigation, all companies denied any wrongdoing. However, both Nestlé and Mead Johnson defended funding conference trips for doctors, even though the Department of Health confirmed it was illegal in the Philippines.

Nestlé said it would “investigate all the reported actions” and “will take fast and decisive action if any wrongdoing is found”.

“This picture does not represent Nestlé’s culture and business practices,” the statement added. “The first and most fundamental expression of our respect for mothers and babies is support for breastfeeding and compliance with the law and our own strict procedures. Nestlé strongly rejects the allegation that it does not comply with its legal obligations and the WHO code as implemented in national law.”

Abbott told the Guardian it was “committed to the ethical marketing of our products in compliance with the laws and regulations of the countries in which we do business,” and added: “The behaviour you have described is not in line with our policies. We take all reports of non-compliance seriously.”

Mead Johnson said it had ”not received notification of the violations you mention. Any reports received by Mead Johnson are investigated according to the facts and information, per our rigorous compliance programme.

“We take great care to fully comply with all established laws and regulations that govern the manufacturing, distribution and marketing of all our products. Acting responsibly is core to our purpose.”

Calibo said the new findings reinforced the need for a change in approach in the Philippines to combat what he described as the “stubborn and cunning” tactics of the milk companies. Currently the majority of violations are reported by mothers themselves, rather than the healthcare professionals being courted by the formula representatives.

“We need a different approach to empower community-based groups to be the ones to report this and inform us,” said Calibo.

“Your findings pull us all back and make us realise that the problem is still there and the monster is still at large. We really have to find a way to cage that monster.”