David Cameron came under renewed pressure to sack his party’s elections adviser Lynton Crosby on Sunday night as environmental activists expressed concern about his links to the fracking industry.

Mr Crosby’s lobbying firm, Crosby Textor, represents the Australian Petroleum Production and Exploration Association, an oil and gas lobby group campaigning aggressively for fracking. The association’s chief operating officer, Stedman Ellis, has made headlines in recent months for his outspoken criticism of anti-fracking campaigners, telling one Australian paper: “The opportunity provided by shale gas is too important to be jeopardised by political scare campaigns run by activist groups.”

The association’s members include Dart, the company behind coal-bed methane extraction in Scotland, which holds a fracking licence. George Osborne announced tax breaks for the oil and gas industry just weeks after Mr Crosby’s appointment as a Conservative adviser was announced.

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Labour will attempt tomorrow to exploit the Tories’ discomfort over their links to Lynton Crosby with a series of amendments to Coalition plans to bring in a statutory register of lobbyists.

The moves follow the disclosure that Mr Crosby’s company is employed by the tobacco giant Philip Morris. Questions have been asked about his role in the decision to shelve Government plans to require tobacco products to be sold in plain packaging. Labour claimed yesterday that Mr Crosby chaired a meeting last year at which tobacco industry executives discussed how to block plans to force cigarettes to be sold in plain packets. The party alleged the session took place before Christmas, shortly before Mr Crosby was recruited to advise the Conservatives on election strategy. Ed Miliband, the Labour leader, said yesterday: “This is beginning to stink as bad as an old ashtray.”

Labour claims David Cameron’s decision to hire Mr Crosby echoed the recruitment of Andy Coulson, who faces charges over alleged phone-hacking during his tenure as editor of the News of the World. A source claimed: “Cameron always makes the wrong decisions.”

Mr Crosby’s links to pro-fracking groups will heap more pressure on the Government to review its policy on the controversial practice, after The Independent on Sunday revealed several top Tories have links to the industry.

A spokesman for the campaign group Frack Off said: “Crosby Textor and their clients are embedded at the heart of government. By smearing groups and communities that oppose shale oil and gas development they are simply trying to further their own financial interests and those of their clients.”

Richard Dixon, director of Friends of the Earth Scotland, said: “Crosby Textor is clearly very involved with the fracking industry. He [Lynton Crosby] should be stepping aside.”

Yesterday the Conservative chairman Grant Shapps accused Labour of a “smear campaign”. He added: “Lynton Crosby advises the Conservative Party on political strategy – he doesn’t advise on policy.”

A spokesman for Crosby Textor in London did not respond to The Independent’s request for comment.