Mr Guaidó has been formally recognised by the US, Europe and several Latin American countries since moving to topple Mr Maduro who won a second term after controversial elections in which opposition candidates were barred from running or jailed. Russia and China back socialist leader Mr Maduro and for now he has managed to retain the support of military top brass which is seen as crucial to his hold on power.
But writing in the New York Times newspaper, Mr Guaidó said secret talks with army chiefs had taken place in recent days.
He said: “The transition will require support from key military contingents.
“We have had clandestine meetings with members of the armed forces and the security forces.
“The military’s withdrawal of support from Mr Maduro is crucial to enabling a change in government.”
The article also says the opposition has offered an amnesty to armed forces “found not guilty of crimes against humanity”.
As head of Venezuela’s National Assembly, Mr Guaidó says the constitution allows him to assume power temporarily when the president is deemed illegitimate.
Venezuela’s Supreme Court has banned the opposition leader from leaving the country, however, and frozen his bank accounts.
Today Venezuela has told dozens of expatriate staff working for Citgo Petroleum Corp in the US they must return to Caracas by the end of February after US sanctions aimed at forcing Mr Maduro from power.
Citgo is owned by Petroleos de Venezuela, or PDVSA , currently controlled by the state and subject to newly-imposed cash controls from Washington.
The recall comes after Venezuelan authorities detained three foreign journalists and a driver working for the Spanish news agency EFE.
Colombian photographer Leonardo Munoz was arrested with his Venezuelan driver Jose Salas while reporting on protests against the government.
Hours later intelligence officers detained Spanish reporter Gonzalo Dom Anguez Loeda and Colombian TV producer Mauren Barriga Vargas at their hotel.
The arrests follow the deportation of two Chilean reporters detained this week.
A French diplomatic source said two French reporters covering the turmoil had been arrested and that the French Embassy was seeking their release.
The deepening political crisis in Venezuela comes after years of decline a the hands of Mr Maduro and his notorious predecessor Hugo Chavez.
More than three million people have fled Venezuela amid acute economic problems, and there has been an upsurge in violence in recent weeks.
US President Donald Trump tweeted that he had spoken to Mr Guaidó and supported his “historic assumption of the presidency”, writing in a second tweet that “The fight for freedom has begun!”
UK Foreign Secretary Jeremy Hunt meanwhile is expected to urge EU nations to impose sanctions on key figures in Mr Maduro’s government today, after also speaking to Mr Guaidó on Wednesday.