Well known in the region, he received the prestigious Ramon Magsaysay Award for his work.
Sombath Somphone has not been heard of since being taken away from a police checkpoint in the capital, Vientiane.
The government has denied any involvement, hinting at a possible business or personal conflict as the reason for his disappearance.
Speaker: Ng Shui Meng, who's high-profile activist husband Sombath Somphone has been missing in Laos for almost three weeks
NG: I have not heard any news apart from the government statement which was issued on the 19th and a visit to the police station I have not heard anything since.
FAYLE: Now have the authorities been maintaining contact with you?
NG: The police department has called me for a short interview on the 26th of December and since then they have not been in contact with me.
FAYLE: Now would you describe your husband as a dissident in any form?
NG: No my husband is not a dissident, he is a very low-profile social development worker interested in helping the country, teaching young people in community service, empowering them, teaching them leadership skills, working with the monks and working with students. He is not at all an activist or a dissident in any way. He has worked closely with the government and with approval of government for every project he has done. So he's not at all an activist, he always believes that as a Lao citizen he wants to support the government to help develop the country.
FAYLE: But he has been involved in a number of land rights and environmental issues has he not, that could possibly have got some people of influence offside?
NG: He has like many concerned Lao been working with local communities understanding the importance of environmental protection, and also empowering them to understand their rights related to their land ownership, which is also very much within the law of the Lao PDR itself. I don't know whether such work would upset any vested interests, but from my own understanding his work has never been provocative. He has also never been in direct contact with any business interests. So far from my understanding of all his work he has always worked with the local communities in cooperation with the local authorities, with the district authorities, with the province authorities.
FAYLE: So are you any clearer three weeks on who has taken him and why?
NG: I'm not clearer than what I have seen on the CCTV footage. The CCTV footage showed that he was last stopped at the police post, that his jeep was driven away by unknown person right at the police post, and he was taken away in a truck which stopped at the police post. That's all I know and that's all I saw and that's also what's been presented to the government. The government has maintained that he has possibly been kidnapped for reasons of personal conflict or business conflicts, and that is all I know.
FAYLE: Now a number of foreign missions, international organisations and prominent regional figures have all been asking questions of the government in Vientiane about your husband. How important has that been?
NG: I think that is very important, not only his family members here want to know, but many of his colleagues around the region and also in-country need to know where Sombath is, and especially to me I need to know where he is.
FAYLE: Now do you fear though that as time goes on that the case may be slipping from the headlines?
NG: My husband's not a headline, he's a person, I hope that he will not slip away and be forgotten, that's why we need to continue to press.
FAYLE: Ng Shui Meng, do you believe that your husband is in police custody?
NG: I don't know. As I said I only believe what I've seen on the CCTV footage, and if the government says it does not have him in custody, I have nothing to counter that either.