THE president of Turkey's president has compared German officials to Nazis, after authorities cancelled rallies designed to woo ethic Turks ahead of a controversial referendum.

About 1.4 million Turkish people living in Germany can vote in the April ballot giving Recep Tayyip Erdogan extensive new powers over the budget, appointment of ministers and judges, and the ability to dismiss parliament.

Erdogan has come under criticism for cracking down on his opponents since a failed military coup last year. Now expatriates eligible to cast a ballot in the referendum are being targeted.

However, officials have withdrawn permission for rallies in Gaggenau, Cologne and Frechen. Addressing them at a rally in Istanbul yesterday, Erdogan said: "I thought it's been a long time since Germany left (Nazi practices). We are mistaken."