A delegation of striking Newsquest journalists, led by Michelle Stanistreet, NUJ general secretary, has met London Assembly members representing the Conservatives, Labour, Liberal Democrats and Green Party.
Meanwhile James Berry, Conservative MP for Kingston and Surbiton, joined the picket line, while Tom Brake, Liberal Democrat MP for Carshalton and Wallington, and Vicky Foxcroft, Labour MP for Lewisham Deptford, have also sent messages of support.
The action was called after members voted unanimously in favour of striking over a proposed cost-cutting drive, which will see many senior roles cut and 16 weeklies placed under a single group managing editor.
Those on strike include staff from the eight-edition South London Guardian series, Elmbridge Comet and the Richmond & Twickenham Times
Colleagues at their sister News Shopper series, in South-East London, staged a walkout on Monday and Tuesday.
The NUJ is demanding a three per cent salary increase and changes to the proposed reorganisation.
In a statement supporting those on strike, Ms Foxcroft said: “The News Shopper in my area, and other local publications owned by Newsquest, are a vital local source of news for many people.
“They play a hugely important role in local democracy and they open up debates for people who do not have the means to engage online.
“Newsquest and the government must do more to ensure jobs are protected and local newspapers stay in circulation.”
Mr Brake tweeted: “I support journalists of @NUJofficial. We should all be worried by threats to local newspapers, which are the bedrock of free speech.”