The party said the capital enjoyed more representation in the Lords than the Midlands and North of England combined.
It published the figures as it presses the case to replace the House of Lords with an elected second chamber representing the “nations and regions”.
Shadow Local Government Secretary Hilary Benn said: “People already know that too much power is concentrated in too few hands.
“It cannot be right that London has more peers than the East Midlands, West Midlands, North West, North East and Yorkshire and Humber added together.
“Labour wants to make sure that every part of the UK has its voice heard in Westminster.
“Our plan for an elected Senate of the nations and Regions will transform the way government works and bring politics closer to people.
“Only then can we be sure that our country is run for all and not just for some.”
Labour has said detailed plans for the new look Senate would be drawn up following its proposed “constitutional convention” which would also consider other issues such as the question of which MPs should be allowed to vote on particular laws given devolution to Scotland, Wales and Northern Ireland. It is expected senators would be elected from nations and English regions rather than constituencies.