The head of Greenpeace UK has defended the need for one of the environmental group's top executives to fly to work several times a month, and apologised to supporters for a mistake that saw a member of its finance team lose £3m on currency markets.

Responding to fresh revelations in the Guardian that the organisation's finance team is in disarray, and that Pascal Husting, Greenpeace's international programme director, flies several times a month from his home in Luxembourg to offices in Amsterdam, John Sauven wrote in a blogpost: "as for Pascal’s air travel. Well it’s a really tough one. Was it the right decision to allow him to use air travel to try to balance his job with the needs of his family for a while?"

He added: "For me, it feels like it gets to the heart of a really big question. What kind of compromises do you make in your efforts to try to make the world a better place?

"I think there is a line there. Honesty and integrity to the values that are at the heart of the good you’re trying to do in the world cannot be allowed to slip away. For what it’s worth, I don’t think we’ve crossed that line here at Greenpeace."

Sauven, the executive director of Greenpeace UK, also addressed internal disquiet over a restructuring that has seen staff moved from Dutch wages in Amsterdam to lower, regional wages around the world. "That’s a pretty hard thing to do and get perfectly right, especially when people’s jobs are involved. Perhaps there are things that could have been done better or differently to communicate better about the planned change and help it happen more smoothly."

On the issue of Greenpeace International's handling of its £58m budget, he apologised to supporters and said improvements had been made. "There’s now a new head of finance, and we’ve put checks in place so that it can never happen again."