CEZ, which is 70% owned by the Czech state, invited bids from the companies for the multi-billion dollar project earlier this year.
"We are happy to confirm the strong interest of all three bidders in constructing a new nuclear power plant in Czechia," CEZ said in a statement.
CEZ will evaluate the bids and send them to the government for final approval, it said, with contracts expected to be signed next year.
"After the final signing of the contracts, the project documentation will be thoroughly prepared so that the new unit will be ready for trial operation in 2036," CEZ said.
The government said in 2020 the project would cost around 6 billion euros ($6.39 billion) excluding inflation, a figure that has likely risen.
EDF said it had submitted its bid to build one EPR1200 reactor at Dukovany, along with more potential units as part of the tender.
"We believe that the long-term strategic partnership we are proposing will set a precedent for our continent and serve as the backbone for a more resilient and independent European nuclear industry," EDF Chairman Luc Remont said in a statement.
Westinghouse, which supplies nuclear fuel to the Czech Republic and also delivered a control system for the Czech Temelin plant in the 1990s, said it was offering its AP1000 reactor which has been chosen by fellow EU members Poland and Bulgaria.
The Czech state has been looking at ways to restructure CEZ to limit the risks of the high-cost project and as part of plans to take more control over energy infrastructure, possibly including a full takeover of its nuclear operations.
The Czech Republic has been a strong backer of nuclear energy as a carbon-free power source for the future, unlike European Union neighbours Germany and Austria, and is planning new plants in addition to new gas-fired and renewable resources.
Any new nuclear units will come too late to immediately fill a gap caused by closure of coal-fired plants in the coming years, meaning the country is likely to turn from electricity exporter to importer for at least some period.
The Dukovany project would initially add one around 1,200 MW reactor to four 500 MW Russian-designed units at the site, but the tender includes an option to build one more at Dukovany and two more at CEZ's other nuclear site, Temelin.
CEZ is also separately looking at building several small modular reactors being developed by various producers. It excluded bidders from China and Russia on security grounds before it launched the tender last year.
