The UAE is withholding cash from its Yemeni allies
The vessels are carrying salaries of government employees who haven't been paid for over a year, the officials, including one from the Yemeni central bank, said.
They were speaking on condition of anonymity
The officials said the UAE had in the past prevented aircraft carrying cash from landing at Aden's airport.
There was no immediate comment from the UAE.
The UAE is a key player in the Saudi-led coalition fighting Houthi rebels, who control most of northern Yemen, including the capital, Sanaa.
However, the Emiratis largely control Aden - a southern coastal port city and the temporary capital of the war-torn country.
The coalition is fighting on the side of President Abed Rabbo Mansour Hadi's government, but the UAE has long been at odds with Hadi, with each side running its own armed groups in a power struggle across southern Yemen.
The latest developments come nearly a year after Hadi ordered the relocation of the Central Bank to Aden. Since then, his rivals have accused him of stashing cash in private banks and in the presidential palace, allegations denied by the government.
The unpaid salaries have crippled Yemen's public sector amid three years of grinding war. Malnutrition, cholera, and other diseases have killed thousands of civilians, and millions have come to depend on humanitarian assistance for survival.
More than 10,000 people have been killed in the Yemen war since 2015, when the Saudi-led coalition joined the government's fight against the rebels.