Despite the fact that millions of euros were spent on the project - the exact amount is a matter of dispute - Latvia has no representation at the Milan fair, which is already open.
The site of Latvia's planned stand has been taken by a cake manufacturer.
On Monday Economy Minister Dana Reizniece-Ozola told the independent LNT TV channel the state would seek to recover around €800,000, from the Expo2015 company set up to organize and coordinate Latvia's participation in the event.
Contrary to some media reports, the Expo2015 in question is not the body organizing the trade fair itself.
Reizniece-Ozola claimed the figure came after a careful audit showed too much had been paid to the Expo2015 company.
However, the company hit back swiftly with its own counter-blast.
In a press statement, Expo 2015 manager Girts Majors said: "We see no justification for the Ministry of Economics claim for a refund made by the Minister this morning."
No request for a refund had been received and in any case would have no legal basis, Majors insisted, while suggesting it was simply the ministry's response to Expo2015's own claim for €185,000 of unpaid bills.
"Our example is a clear warning to any private businesses of how risky, unsound and unpredictable it can be to cooperate with the state.
"The Ministry of Economics continues to conduct our mutual relations via the mass media... rather than resolve differences through negotiation," Majors said.
The Latvian cabinet in January backed Reizniece-Ozola's recommendation to can the EXPO project after it seemed likely Latvia would be unable to complete its ambitious wooden stand in time for the opening of the exposition in May.