DUBAI, July 19 (Reuters) - Human Rights Watch called on the United Arab Emirates on Monday to allow hundreds of Palestinians and Lebanese nationals expelled from the Gulf Arab state in the past year to appeal their deportation.

The US-based rights group said in a report that the Palestinians, mostly from Gaza, and Lebanese had been expelled by the UAE without explanation.

Palestinian and Lebanese officials had reported the deportations last year. The UAE has never confirmed the claims.

A UAE Interior Ministry official had no immediate comment on the HRW report.

The government has yet to give any adequate justification, Sarah Leah Whitson, the Middle East director of HRW, said, adding that many of the deported families had lived in the UAE for several decades.

The deportations followed tensions after Israel's December 2009 war on Gaza, where the 1.5 million residents have been under blockade since the Islamist group Hamas took power.

The war sparked friction between US-allied Arab states like the UAE and militant groups supported by Iran, including Hamas and the Lebanese Shi'ite group Hezbollah.

Deported Lebanese nationals interviewed by HRW said they had been interrogated about their political affiliations, including over alleged links to Hezbollah.

The interrogations raise concerns that the expulsions were politically motivated, Human Rights Watch said.

The organisation, citing the Beirut-based Committee for Lebanese Deported, said the UAE has deported at least 120 Lebanese families, all Shi'ite, since June 2009.

Human Rights Watch called on the government to publicly state the necessary steps residents could take to appeal their expulsion, and suspend deportation pending an appeal.