If the proposal being voted on today is passed the move will still leave 26 UK seats open, which the bloc will redistribute to make up for biases in representation.
MEPs have struggled to agree on the fairest way to share out the seats, with the outcome potentially shifting the balance of power in the EU’s Parliament.
The final decision could shape European democracy for years to come.
A controversial part of the proposed amendment discusses whether MEPs will allocate some of the seats to EU-wide candidates, transnational members who would represent the interest of the whole bloc rather than a specific country.
The EU parliament has floated the idea of transnational lists since 2011, but it was deemed unlikely until the UK voted for Brexit in 2016.
The Italian government has backed transnational lists and the idea has long been supported by European federalists.
Critics have slammed the idea claiming it would make Brussels look more out of touch and less democratic.
Kazimierz Ujazdowski MEP, constitutional affairs spokesman for the European Conservatives and Reformists group, said: “This is a flagship idea of European federalists who naively assume it will increase accountability and participation in European elections when it will do the exact opposite.”
Swedish MEP Gunnar Hokmar said: “These transnational lists are neither European nor democratic.
“They will further undermine the relationship between the electorate and the elected ones.”
The debate over transnational lists has effectively been postponed, as MEPs lean towards an idea that will redistribute 27 seats and keep others in reserve.
There is still disagreement as to what would be fair representation.
France has stated that each its of MEPs have an electorate of 900,000, the equivalent amount for Slovakia, Bulgaria, Finland, Ireland and Denmark have less than half of that.
Under a compromise being voted on today, Italy and Holland will increase their number of seats by three.
France and Spain will gain five additional seats.
Ireland is thought to be getting two more, while Finland, Slovakia, Croatia, Estonia, Romania, Poland, Austria, Denmark and Sweden will all get one.
The full EU Parliament will vote on the proposal in early February, before submitting it to the European Council for approval.
A Parliament official who didn’t want to be named said it was likely the European People’s Party (EPP) group would vote in favour of the amendment on transnational lists.
The EPP is a transnational party comprised of political parties than individuals.
Its leader is the President of the European Commission Jean-Claude Juncker, while its Vice President is the Brexit negotiator Michel Barnier.
The legal basis of transnational lists “comprising the entire territory of the Union” will need to be provided by a future council decision.
MEPs have said in the compromise amendment that those elected on transnational lists would only take up their seats after the UK has left the European Union.