A Conservative government would be likely to ban Scotland's MPs from voting on issues which only affect England, party sources have indicated.
Mr Cameron has called for more 'fairness' at Westminster
The party's democracy taskforce is expected to recommend the policy when it publishes a report this summer.
A Tory source said it was necessary to address "longstanding" complaints about Scotland's MPs being able to vote on English issues but not vice-versa.
Party leader David Cameron has called for a more "fair approach".
The Conservatives currently have just one Scottish MP, whereas Labour has 39, the Liberal Democrats 12 and the Scottish National Party six.
A Tory spokeswoman said: "We are looking at voting options. We are expecting a full report over the summer at some point."
Mr Cameron has said he wants to keep the 300-year-old union of England and Scotland, but that the "imbalance" needs to be fixed.
Scotland has had its own Parliament, with powers over education, health, the environment, home affairs and to alter income tax, since 1999.
This has led to criticism of a system in which Scotland's Westminster MPs are still able to vote on English affairs.
End of Union?
However, if the change came in, Scotland's Westminster MPs - including current Chancellor Gordon Brown and Home Secretary John Reid - would not be able to vote on issues solely relating to England, Wales or Scotland.
Critics of the Tory proposal say this could cause the end of the Union established between England and Scotland 300 years ago.
But Mr Cameron insists this is a matter of "fairness" and that, if the policy is implemented, it would strengthen the Union.
The democracy taskforce, headed by former Chancellor Ken Clarke, has been charged with looking at "problems arising from Tony Blair's constitutional changes such as the West Lothian (or more accurately) the English question".
The so-called "West Lothian question" first came to prominence when highlighted by the former West Lothian - and later Linlithgow - Labour MP Tam Dalyell.
Mr Dalyell said devolution would fuel resentment if Scottish MPs continued to vote on matters which affected only England.
Labour MP and former minister Frank Field has put down an early day motion calling for MPs not to vote on matters "which are devolved to their respective countries".