UAE authorities repeated that fundraising and collecting donations is against the law, unless partnered with a registered charity.
Prosecutors said anyone who wanted to help the needy during Ramadan should do so through legal channels only.
Charitable acts are obligatory for Muslims during the holy month.
But there are strict laws governing the collection of donations in the UAE.
Under Article 27 of the Federal Law No 5 of 2012 on Combating Cybercrimes, it is illegal to call for, promote and collect donations online without first obtaining the proper permission and licensing from the relevant authorities.
In a video posted on social media, prosecutors highlighted penalties related to the law.
They include jail time and “a fine not less than Dh250,000 and not in excess of Dh500,000, or either of these two penalties for whoever establishes, manages or runs a website or publishes information on the computer network or any information technology means to call or promote for the collection of donations without a licence accredited by the competent authority”.
Anyone found collecting donations or contributions at mosques, without first obtaining permission "shall be sentenced to imprisonment for a maximum of three months and a fine [up to] Dh5,000 or either one of the two penalties".
On Tuesday, Dubai Police arrested 12 people in an operation to tackle begging.
The arrests were made as part of a campaign being run under the slogan "begging is misunderstood for compassion".
Every Ramadan, police arrest hundreds of beggars, many of whom are believed to come to the UAE on visitor visas.
Firing of the Ramadan cannon - in pictures
