(Reuters) - Britain's opposition Labour Party is considering raising capital gains tax and altering inheritance tax to help fund public services if it wins the July 4 election, the Guardian newspaper reported, citing sources and documents.

An increase in capital gains tax could raise 8 billion pounds ($10.10 billion), the Guardian said.

Labour also wants to make it harder for people to gift money and assets under the inheritance tax regime. In total the measures could be worth 10 billion pounds, the Guardian said, citing a document from the party.

The Labour Party was not immediately available for comment.

Opinion polls show Labour is on course for a huge majority in parliament.

Its leader Keir Starmer has pledged not to raise the main taxes paid by working people, and has sought to push back on any suggestion that a Labour government could have an immediate big impact on issues like the cost of living and standard of public services.

Prime Minister Rishi Sunak's Conservatives have sought to turn the spotlight onto tax, saying a Labour government would cost households more.

However, the tax bill is already at a 70-year high and will continue to rise even if the Conservatives win because both parties have pledged to freeze tax thresholds.

($1 = 0.7921 pounds)

(Reporting by Andy Bruce; Editing by Sachin Ravikumar)