The iconic Washington Post newspaper has been left "very embarrassed" by a mistake that took up the entire front page of one of its daily inserts.

The Washington Post Express cover was devoted to a story about an historic women's rights march that is scheduled to happen in the US capital the day after Donald Trump is sworn in as President.

However, there was a problem.

The illustration of women en masse was supposed to be in the shape of the symbol for women. But the men's symbol was used by mistake.

Social media users jumped in to point out the clanger.

The newspaper responded quickly by apologising and issuing an alternative cover on its digital platforms.

"We made a big mistake on our cover illustration this morning and we're very embarrassed about it," the paper said. "This is how the cover should have looked. We apologize for the mistake"

However, the improved cover also copped a lot of backlash, for being "feminine-hygiene-packaging pink", among other jibes.

"Not good enough," wrote one critic. "Dozens of your staff, managers, supervisors and editors had their eyes on this. None of them caught it? You need to hire some competent women to replace your incompetent men in key staff positions."

The gaffe came on the same day that Yahoo Finance also made an unfortunate error.

The internet giant tweeted a story about Trump's plans to make the US navy larger.

Instead of writing 'bigger', it started the word with an 'n' instead.

Yahoo Finance says a racially offensive tweet was a spelling error. Photo: Twitter

Yahoo Finance apologised for the spelling error and deleted the tweet, but it had already been shared more than 100 times.

Social media was quick to react to the error.