Tory eurosceptics are using a campaign for the abolition of the so-called "tampon tax" to push demands for a more far-reaching renegotiation of the UK's relationship with the European Union.
Several have signed up to a Labour amendment in the Commons which would commit the Treasury to challenging a Brussels ban on member states unilaterally exempting goods and services from tax.
Campaigners argue that it is ridiculous for the items to be classed as a "non-essential luxury item", especially when books and newspapers, motorcycle helmets and other products are zero-rated.
But Tory rebels also hope that by joining with opposition parties in a Commons vote, they could cause Prime Minister David Cameron a fresh headache over Europe.
Labour cut the rate from the then standard rate of 17.5% - imposed in the 1970s - to the lower rate of 5% in the 2000 Budget, but was prevented from going any lower by the European rules.
An amendment tabled to the Finance Bill and backed by shadow chancellor John McDonnell would require Chancellor George Osborne to publish within three months a strategy for negotiating an exemption - and an update on progress by April next year.
Bernard Jenkin - one of 11 Tories to have put his name to the amendment which Labour expects to be selected for debate - said he believed many more would be prepared to vote with the Opposition.
He said there was a good case for reform as it was "hardly a choice for women that they have to buy sanitary products".
But he also made clear that he hoped a Commons victory on the issue would help the case of those seeking Britain's exit from the EU.
"This is an example of where the EU has taken over jurisdiction over our tax where it should not have. The UK Parliament should be able to set whatever taxes it wants.
"If you can't renegotiate something like this, it underlines why we need a new relationship outside the treaties."
Ukip health spokesman Louise Bours said: "The only way we are going to get rid of this ridiculous tax, is for politicians to start listening to the electorate, decide they will do what is best for their voters, not the 'project', and leave the EU.
"Once we leave the EU we can act swiftly, follow in Canada's footsteps and get rid of this archaic tax on feminine hygiene products.
"The tampon tax is nothing short of a tax on women. David Cameron clearly doesn't have a problem with that, but I think he'll find almost the entire country will disagree with him."
SNP MP Alison Thewliss said: "It is absurd that while men's razors, children's nappies and even products like Jaffa Cakes, exotic meats and edible cake decorations are free from VAT, women are still having to pay additional costs on what is already an expensive yet vital product.
"The failure of this Tory Government to negotiate the abolition of VAT on sanitary products over a period of five years suggests that either they are inept or they aren't genuinely committed to ending this unfair tax on women."
A Treasury spokesman said: "The UK has set the VAT on sanitary products at the minimum rate permissible under EU rules."
Any change would require a Commission proposal and the unanimous agreement of all 28 member states.
There appears to be little or no appetite for such a move in some other EU countries however.
The French parliament recently threw out a bid by socialist MPs to cut tax on sanitary products from 20% to 5.5%, which the Paris government said would have cost it £40m in lost revenues.