London: Summer days are growing hotter in the world's big cities at a significantly faster pace than the average rise in world temperatures.

It is a trend that could mean more deadly urban heatwaves in years ahead, scientists have claimed.

A tennis fan does his best to keep cool on day four of the Australian Open in Melbourne, this week. Credit:AAP

The trend is particularly pronounced in parts of Australia, Europe and, East Asia, a report released in the journal Earth's Future said.

In cities such as Paris, Houston, Moscow and Beijing, heat on the hottest summer days is growing two or three times as quickly as general temperature rises linked to climate change over the last 50 years, said researchers at the University of California-Irvine.