Tories have dismissed questions over whether David Cameron's election guru influenced coalition policy on tobacco packaging.
Party chairman Grant Shapps hit out at "smears" after Labour asked the Cabinet Secretary to examine Lynton Crosby's involvement in putting off the introduction of plain cigarette packets in England.
Mr Crosby's public affairs firm has reportedly been advising tobacco giant Philip Morris in this country since November.
But Mr Shapps told the Murnaghan programme on Sky News: "First of all, every policy which is decided upon by the Government is decided upon by the coalition... the Lib Dems and Conservatives. Lynton Crosby advises the Conservative Party on political strategy; he doesn't advise on policy."
Mr Shapps added: "This is looking like a smear campaign."
He said Australia was currently the only country in the world adopting plain packaging, and there was "no evidence one way or another" whether it worked. "This country has a good record on reducing smoking," he said. "We are not at all afraid to take steps. We want to take steps based on evidence."
Ministers had previously expressed strong support for the cigarette packaging proposal, designed to make smoking less attractive to young people. All packets would be the same colour, with the same text font, and carry a graphic health warning.
However, the Government announced last week that a decision had been delayed after a consultation found views were "highly polarised".
Labour frontbencher Jon Trickett has asked the Prime Minister to give details of Mr Crosby's involvement in government policy-making. He has also urged Cabinet Secretary Sir Jeremy Heywood to explore whether a breach of the ministerial code has occurred - although Mr Cameron would have to sign off on any such probe.
Liberal Democrat former health minister Paul Burstow told the Observer: "Lynton Crosby cannot remain at the heart of government while he is also serving the interests of the tobacco industry. If he does not go, the Prime Minister should sack him."