Expedia, the world’s largest online travel company, has declined to follow the lead of other big internet firms, instead choosing to remain a member of a controversial rightwing lobby group that works against climate change legislation.

The travel company pays dues to the American Legislative Exchange Council (Alec), a secretive lobby group that shapes and promotes legislation at state level across the US. Sources close to the organisation said it is part of Alec’s tax and fiscal policy taskforce, and has paid thousands in dues.

Expedia, whose membership of Alec has not previously been disclosed, declined to comment.

Alec has attracted criticism for its opposition to legislation that would curb carbon emissions, as well as anti-union policies and other extreme rightwing proposals at the state level. A range of tech firms have dumped Alec recently because of its stance on climate change.

This week, Google, Facebook and Yelp became the latest companies to quit Alec over its environmental stance. Yahoo initially stood by its membership before conducting a swift pivot in the face of online criticism.

Alec’s bad week started with Google chairman Eric Schmidt saying the company could no longer be aligned with people who deny climate change.

“The people who oppose it are really hurting our children and grandchildren and making the world a much worse place,” Schmidt said on NPR’s Diane Rehm Show. “We should not be aligned with such people. They are just literally lying.”

Microsoft, which used to own Expedia, quit Alec in August, again over its lobbying against climate change legislation.

Many companies have been the subject of fierce lobbying campaigns by groups opposed to Alec’s policies. Expedia is likely to face similar pressure. The company, which also owns Hotels.com and Hotwire.com, has in the past championed sustainability and promotes carbon offsets for passengers worried about the climate impact of their travel.

“Expedia has taken a huge gamble with its reputation by joining Alec, especially now when there is so much activism around climate change. No group does more to block action on climate change than Alec, and with so many competitors to Expedia in its own market, informed consumers may choose to look elsewhere online to book their next hotel room because of this,” said Nick Surgey, Director of Research at the Center for Media and Democracy.

On Thursday, Alec hit back at charges that it was lobbying against climate change legislation.

“The facts are: Alec recognizes that climate change is an important issue and just hosted a roundtable conversation for a variety of companies – including Google – on this very issue … The organizations that pressured you consistently conflate climate change denial with having significant concerns over government mandates, subsidies and climate regulations,” it said in a letter.

The rebuttal was challenged by two of the organizations it accused of mounting the pressure – the watchdogs the Center for Media and Democracy, and Forecast the Facts. They said Alec was “unequivocally a climate denial organization that cloaks its polluter agenda in free-market rhetoric.”

The organisations pointed out that at the network’s most recent meeting in Dallas, Joseph Bast, president of the rightwing Heartland Institute, led a workshop in which a presentation was made that denounced the UN’s Intergovernmental Panel on Climate Change (IPCC), which has produced some of the most authoritative accounts of global warming, calling it “not a credible source of science and economics”.

The tech exodus follows a falling out with several other major US corporations.

Last year the Guardian disclosed that Alec was trying to woo back lapsed corporate members including Amazon, Coca-Cola, General Electric, Kraft, McDonald’s and Walmart, all of which cut ties with the group following the furore over the killing of unarmed teenager Trayvon Martin in Florida in February 2012. Alec had championed “stand your ground” laws similar to one on Florida that initially led police to say they could not arrest Martin’s killer, George Zimmerman. Zimmerman was ultimately acquitted.