Romania's president sparked fresh political turmoil Tuesday after blocking a proposal by the leftist party that won elections this month to appoint the EU country's first female and first Muslim prime minister.

Klaus Iohannis gave no reasons for his rejection of Sevil Shhaideh, put forward by the Social Democrats (PSD), but there was speculation that it was due to her Syrian husband's background.

The PSD had suggested the previously little-known Shhaideh, 52, after its thumping poll victory on December 11 when it won 45 per cent of the vote.

"I have properly analysed the arguments for and against and I have decided not to accept this proposal," the president told reporters, calling on the PSD to "make another proposal".

Shhaideh, 52, who has only five months ministerial experience, is from Romania's small and long-established Turkish minority, but her Muslim faith is not thought to have been the problem.

Instead the focus was likely on her husband, 54, who worked in the Syrian agriculture ministry for 20 years before emigrating to Romania in 2011 and marrying Shhaideh the same year, according to the PSD.

Non-profit investigative journalism group the Rise Project said that he has several times expressed his support for Syrian President Bashar al-Assad and for Lebanese Shiite movement Hezbollah.

Website HotNews cited unnamed sources as saying that the security services had "strongly cautioned" against Shhaideh's nomination because of the closeness of her husband and his two brothers to the Assad regime.

This might have made giving Shhaideh the necessary security clearances to be the NATO member's prime minister problematic.

"I suppose that his rejection is linked to questions of national security and because the United States would not have been very keen," political analyst Andrei Taranu told AFP.