LONDON, Feb 5 (Reuters) – Britain must be able to tackle any abuse of its welfare system by migrants, but that cannot come at the price of discriminating against EU citizens, European Parliament President Martin Schulz said on Friday.

Limiting welfare payments to migrants is a key plank of a reform package that Prime Minister David Cameron wants EU leaders to approve ahead of a referendum on British membership of the bloc that may be held as early as June.

In a speech at the London School of Economics (LSE), Schulz questioned whether measures proposed by European Council President Donald Tusk allowing Britain to curb benefits to EU migrants were a fair way of dealing with high rates of migration.

He made a comparison between hypothetical workers – Claudia, a Germany national, and John, a British citizen, both employed by the LSE. While she is denied in-work benefits – payments to lower paid workers – John is not, despite both paying taxes.

“Is this the European Union we want to live in” he asked, according to a transcript of his speech.

“The European Parliament will support all proposals which fairly address real problems which may emerge from free movement, as long as they do not cause discrimination and undermine European values.”

The European Parliament will have to pass legislation to implement parts of any deal on the British reform package that may be struck at a summit of EU heads on Feb. 18-19.

A proposed “emergency brake” on benefits for EU migrant workers and safeguarding procedures for non-euro countries on financial regulation would both have to be put into EU law by the council of ministers and the parliament.

Cameron’s demand to curb benefits to EU workers has become the one of the most difficult points of his attempt to win Britain a better membership deal with the 28-member bloc.

Several eastern European countries have balked at the idea that their citizens, who have moved to Britain in their tens of thousands, might be treated differently from British workers, saying that would go against the principle of free movement of people.

Earlier on Friday however, Cameron seemed to win support from Poland’s Jaroslaw Kaczynski, who as head of the ruling Law and Justice party is viewed as the ultimate decision maker in Poland.

(Reporting by Elizabeth Piper; editing by Stephen Addison)