Liam Fox is facing criticism for preaching "shared values" with the Philippines as he met its president Rodrigo Duterte, who has bragged of personally killing suspected criminals.
International Trade Secretary Dr Fox, whose department was created after the EU referendum to promote worldwide trade, made the comment as he called for closer ties with the nation.
More than 7,000 people have been killed in Mr Duterte's campaign against drugs, according to police figures, causing widespread condemnation.
He has also urged the public to kill drug addicts, who he said he would be "happy to slaughter" in their millions.
In an article for the Philippines' Business World, Dr Fox wrote: "The UK and the Philippines have a well-established and strong relationship built on a foundation of shared values and shared interests and we want this partnership to continue to flourish."
His comments came ahead of Prime Minister Theresa May's meeting with King Salman of Saudi Arabia on Wednesday.
Labour MP Harriet Harman, chairwoman of the joint committee on human rights, told the Guardian: "There is a real danger that in our desperation to conclude trade deals respect for human rights, which is in every EU contract, will just go out of the window.
"The Government must not let that happen."
Shadow international trade secretary Barry Gardiner added that Dr Fox's comments were "frankly shocking".
"I'm sorry, but we do not have these shared common values with president Duterte who wants to bring back the death penalty and lower the age of criminal responsibility to nine," he said.
Liberal Democrat foreign affairs spokesman Tom Brake added: "Duterte is one of the 21st century's most sinister leaders and Liam Fox has flown halfway around the world to grovel to him.
"The fact that the first visit made by Fox since triggering Article 50 is to the Philippines shows just how low this government is willing to stoop in order to secure even a minimal trade deal in the future.
"No amount of pandering to corrupt regimes can replace our membership of the single market, which is why the Liberal Democrats will continue to fight against the hard, divisive Brexit this government is pursuing."
Mr Duterte provoked outrage in December after he told business executives how he used to hunt down suspects himself to set an example when he was mayor of his home city of Davao.
"In Davao I used to do it personally. Just to show to the guys (police) that if I can do it why can't you?" he said.
"I go around in Davao with a motorcycle, with a big bike around and I would just patrol the streets and looking for trouble also. I was really looking for an encounter to be able to kill."
A Department of International Trade spokesman said closer ties would help Britain to address areas of concern.
He said: "We do not shy away from confronting barriers to trade and investment - including issues of human rights and corruption.
"Greater knowledge and understanding of one another will increase our ability to address those issues that concern us."