Boris Johnson said the Middle East city has adopted an aggressive strategy to attract global finance and London must rise to the challenge if it wants to "emerge from the downturn stronger than ever", Arabian Business stated.
The mayor's comments follow a report which identified Dubai's tax-free status and rapid economic growth as serious threats to London's position.
"It is clear there are challenges that must be overcome if London is to retain its global status, particularly during the current economic downturn," Mr Johnson commented.
Other challengers to the city include Singapore, Dublin, Bermuda and Luxembourg, the report said.
Elsewhere, financial industry recruitment specialist Taylor Hofer told the publication that despite the global downturn, demand for banking executives remains strong in Dubai.