Sadiq Khan is urging the government to give London boroughs the power to hike council tax on empty mansions.
The London mayor commissioned research into the extent of foreign home ownership in the capital last year, and the findings revealed that the number of empty homes was low, and concentrated in prime areas.
However, Khan said today that in London "just one home left unoccupied is one too many".
He did not specify what rate should be applied, but that the charge should be at a level that "makes a difference".
In a letter to government, the London mayor recognised the importance of encouraging people to live in their London homes, but said higher council tax rates on some properties could help fund the building of affordable homes and other housing measures.
City Hall has already secured £3.15bn in funding from central government to help build 90,000 affordable houses. The mayor has also invested £25m into Pocket Living, a developer that uses off-site construction to build affordable homes for first-time buyers in the capital.
Khan said: "The housing crisis is the biggest challenge facing our city today and I've been honest with Londoners from the start - we won't change things round overnight."