"The Master of a merchant vessel reports an explosion in close proximity to the vessel, vessel and all crew are safe," UKMTO said in an incident report.
The explosion happened at 4:35 GMT some 180 nautical miles east of the town of Nishtun in southeastern Yemen. The ship proceeded to its next port of call.
UKMTO advised all vessels to transit with caution and report any suspicious activity to the navy, pending an investigation.
Yemen's Houthi movement, which controls most of the Yemeni Red Sea coast, said in October it would attack any ships associated with Israel, in a show of support for Palestine. The rebels said they did not want to interfere with freedom of navigation in the region and would not target ships of other countries. Some shipping companies rerouted their vessels to avoid the Red Sea.