Culture Secretary Sajid Javid has indicated that he may join Tory backbenchers voting against Government plans to force cigarettes to be sold in plain packs.
Mr Javid said he was "not sure if there's enough evidence yet" from a similar reform in Australia but was still to make up his mind which way to vote.
Public Health Minister Jane Ellison announced last week that the Government would table regulations to enforce standardised packaging in England by May 2016.
The firm backing of Labour and the Liberal Democrats should be sufficient to see them approved by the Commons - but up to 100 Conservatives are re ported to be poised to vote against.
"I will be driven by the evidence. I haven't decided yet which way I'm going to vote," Mr Javid said.
While the Government had "a duty to try and discourage people" a lot was already being done, said the Culture Secretary.
Last year standardised packaging was introduced in the Republic and the move has been discussed by the MLAs at Stormont.