Ukraine's President Volodymyr Zelensky referenced "Star Wars" and World War II as he sought aid from big tech firms on Thursday, appearing as a hologram at a conference in Paris.

He told a crowd of hundreds at the VivaTech trade show that Ukraine was offering technology firms a unique chance to rebuild the country as a fully digital democracy.

He asked for help on the terms of lend-lease -- the way in which the United States helped the Allies during World War II, whereby aid was offered without payment but on the understanding that hardware would be returned.

"It's unusual for presidents or heads of government to use a hologram to address people but this is not the only aspect of 'Star Wars' that we are putting into practice," he said.

"We will defeat the empire too," he said, obliquely likening Russian forces to the bad guys in the "Star Wars" franchise.

He said the government would lay out the specifics of a plan that would create a digital government at a conference in Switzerland in the coming weeks.

"No other country in the world will offer you such a chance to use the most advanced technologies at a state level," he said.

"It's an experiment and a digital revolution, and the modernisation of the current system all at the same time." Ukraine has won praise for its use of technology during the war with Russia, utilising crypto communities to raise funds and even successfully appealing to Elon Musk to supply the infrastructure for satellite-based internet services.

Russia invaded Ukraine on February 24 and has waged war on cities across the east and the Black Sea coast, in what Ukrainians say is an attempt to destroy their country.