Photo: Ahn Young-joon/AP

The International Olympic Committee on Friday approved a mixed 4x400m relay along with 14 other events for Tokyo 2020, hailing the move as "an important step for gender equality" at the Games.

IOC sports director Kit McConnell said the Tokyo Games would include 321 events, up from 306 at Rio 2016, with 3-on-3 basketball among the new additions.

"We have taken a really important step forward in terms of gender equality," McConnell told reporters in Lausanne, after the mixed relay and mixed swimming events were approved.

He added there had been "a larger number of request" from federations to beef up the Tokyo Games, but that IOC was focused on appealing to "young and urban audiences", as well as redressing long-standing in balances between male and female athletes.

Mixed triathlon will also appear at Tokyo for the first time, along with a mixed team archery event and BMX freestyle.

"The fascinating new events that we approved today, together with the five new sports that were added to the Tokyo 2020 programme last year, represent a step-change in the Olympic programme," IOC chief Thomas Bach said in a statement.

In total, the number of mixed events at Tokyo will double to 18 from 9 in Rio, the IOC said.

The body's executive committee, meeting at IOC's lakeside headquarters in Lausanne, also managed to trim the number of total athletes competing by 285 compared to Rio, another key priority to guard against the Games growing increasingly bloated and costly.