Green Party leader Trevor Sargent and his wife, Green Party councillor Heidi Bedell, are among 40 climbers embarking on a trek across the Andes in Peru this week to raise funds for the Irish Guide Dogs for the Blind.
The group, which includes visually-impaired as well as sighted participants, aims to raise more than €150,000 to help train guide dogs.
The guide dogs association estimates that each animal costs up to €35,000 to breed and train.
The group will leave Dublin airport for Peru on Thursday morning to undertake the 70km trek from Cusco to Machu Picchu at 4,500m in the Andes.
Mr Sargent, who hopes to raise €7,000, said the trek was both a physical and a financial challenge.
"Financially, Heidi and I are deeply grateful for the generosity of fellow Greens and the local community in Dublin North and beyond.
"We are now very hopeful that our target will not only be reached but exceeded."
He said he was a great admirer of the work of the Irish Guide Dogs for the Blind, and was grateful for the opportunity to take part in the trek.
"Getting time to train has not been easy, and finding a mountain in Dublin North was even more difficult. We are grateful to the various hillwalking groups which helped us prepare for the trek. Our plan is to face and meet the challenges ahead, both physically, financially and, indeed, politically when we return on September 11th."
Dubliner Tina Lowe, one of the participants on the trek, said a guide dog changed her life after she lost her sight in 1993.
"A dog gives you back your independence. You can go where you want, and lots of things are suddenly possible."
Ms Lowe, who works with disability recruitment agency Ahead, lost her sight after a virus attacked her optic nerves while she was living in Spain in the early 1990s.
She believes that people act more normally around blind people who have guide dogs, rather than canes. However she said: "Many restaurants, taxi drivers and shop owners in this country are still unaware of legislation that means they must admit guide dogs."
Irish Guide Dogs for the Blind brings mobility and independence to the lives of the blind and visually-impaired.
