kissing an ofw in front of a public event in another country is so unethical, the line between ethical and unethical, moral and immoral are blurred to duterte as long it serves his personal interests 🤷🏻♀️ goodluck, Ph
"His repeated acts of machismo are meant as entertainment to hide the reality of his rapidly slipping popularity due to the issues of extrajudicial killings, the Tax Reform for Acceleration and Inclusion law and big-time corruption scandals now plaguing his rule," it said in a statement on Monday.
The woman - identified as Bea Kim - was later quoted by the Philippine News Agency as saying that the president had asked if she was single, to which she responded that she was married to a Korean.
She said that there was "no malice" in the kiss, adding that the incident didn't "mean anything except to entertain and make other Filipinos in the gathering happy".
Mr Duterte has sparked outrage before with a string of comments seen as misogynistic.
In April 2016, he spoke to an election campaign rally about the 1989 murder and rape of a female Australian missionary in Davao, where he was mayor at the time.
"I was angry because she was raped," he said. "That's one thing. But she was so beautiful, the mayor should have been first, what a waste." His office later apologised for the comments.
Earlier this year Mr Duterte told Filipino soldiers they should shoot female communist rebels in the vagina.
Both incidents lead to strong criticism and a backlash on social media.
'Strong, assertive image'
Howard Johnson, BBC Philippines reporter
Despite a string of accusations of misogyny against the president, he remains popular both in the Philippines and with Overseas Filipino Workers (OFW).
OFWs I've spoken with say they like Mr Duterte because he projects a strong, assertive image of the Philippines; a father figure to look after the country and its children while they are working abroad.
On a recent trip to the UK, I met a Filipino nurse working in a hospital in London. She said she thought the Western media were biased against the president and didn't report news about him accurately.
Critics of the government say that many OFWs are targeted by pro-government bloggers on social media feeds. They say postings on platforms like Facebook and Twitter spin an inaccurate, glowing image of the president.