Prince Harry and Meghan Markle have taken to social media to call for "compassion" in the wake of a barrage of public criticism.

The Duke and Duchess of Sussex shared a post on their official Instagram account, which featured a quote by the Dalai Lama.

"I believe that at every level of society — familial, tribal, national and international — the key to a happier and more successful world is the growth of compassion."

The royal couple has faced an avalanche of negative publicity over the past few months.

Last month, the Duke and Duchess of Sussex were accused of hypocrisy for taking four gas-guzzling private jet flights in just 11 days, while encouraging others to do their bit for the environment.

View this post on Instagram

A quote for the week ahead. The 14th Dalai Lama, Tenzin Gyatso, is a spiritual leader and a man of peace. Through this approach he has received over 150 awards, honorary doctorates, and prizes in recognition of his message of peace, non-violence, inter-religious understanding, universal responsibility and compassion.

A post shared by The Duke and Duchess of Sussex (@sussexroyal) on Sep 17, 2019 at 7:03am PDT

The couple also suffered intense criticism for their decision to keep their son Archie's christening private after receiving a taxpayer-funded renovation to their Frogmore cottage home.

Earlier this month, current affairs show 60 Minutes delved into how the Duchess of Sussex's bad PR is causing a "royal crisis" - and how the former actress went from "adored to insufferable" in less than a year.

British TV personality and former friend of Meghan Markle, Lizzie Cundy, was interviewed for the show.

In the episode she revealed Markle had asked her for help finding a "famous" British boyfriend back in 2013.

"The girl I knew changed to a girl that maybe was more manipulating," Cundy said.

"She wanted a celebrity boyfriend."