"We don't want to be preachy, we just say those words (fair trade), and make sure people look it up themselves," Martin said at a news conference in Hong Kong ahead of a Coldplay concert Thursday.
Coldplay supports Oxfam's fair trade campaign, which lobbies against trade policies that hurt developing countries, such as the influx of goods from developed countries.
Martin said the band wants to put its name recognition to good use.
"When one or two people take pictures of us, we feel like we could start advertising something we care about," said Martin, who has the Oxfam campaign's twin-striped logo tattooed onto his left hand.
The band also said Thursday they dislike their debut album "Parachutes," released in 2000.
"We know that's terrible music, and we always try to think about what we can do next," Martin said.
Martin declined to say when the band will release its next album, but said it definitely won't be this year.