Aussie cartoonist labelled sexist for portraying Helen Clark in an unflattering light alongside Kevin Rudd

An unflattering cartoon featuring former New Zealand Prime Minister Helen Clark has been slammed as 'sexist'.

Bill Leak's cartoon of Helen Clark and former Australian Prime Minister Kevin Rudd was published in the Australian newspaper today.

In the cartoon a smiling Mr Rudd says: "Heaven forbid the next UN Secretary-General will be yet another man in a blue tie, eh Helen?"

A scowling Ms Clark replies: "It's not a beauty contest, Kevin".

Ms Clark confirmed on Tuesday she is running for the role of Secretary General of the United Nations.

There's speculation Mr Rudd will run for the post too, but he's yet to make an official announcement.

Mark Di Stefano, Political Editor of BuzzFeedOz, condemned the cartoon, tweeting: "Bill Leak is just so consistently a sexist prick".

The tweet was met with a range of comments supporting Mr Di Stefano's view including Twitter user @GlavenCrocker who wrote: "I'd much prefer Helen Clark than Mr. Narcissist".