Posting photos of himself and Rudolph Guiliani on Facebook, MP Andriy Derkach said they had also talked about “ineffective use of American tax dollars by Ukrainian government representatives”.
The lawmaker earlier claimed to have evidence of US presidential candidate Joe Biden and his son Hunter receiving lobbying money from gas company Burisma.
The allegations are at the centre of a probe into whether Trump pressured Ukraine to launch an investigation into Biden.
Democrats are preparing impeachment charges against the US president on the grounds that he, with Giuliani’s assistance, solicited foreign interference in US elections for his personal needs.
Derkach, a former ally of ousted pro-Russian president Viktor Yanukovych, has held several press conferences in recent months accusing Hunter Biden of receiving Ukrainian money “by criminal means.”
The New York Times reported earlier that Giuliani, who is reportedly under investigation himself in the US, had travelled to Budapest on Tuesday and Kiev Wednesday.
According to the Times, the former mayor of New York was also meeting with former Ukrainian prosecutor, Yuriy Lutsenko, a central figure in the impeachment case Democrats are building against Trump.
Lutsenko’s spokeswoman confirmed on Thursday that the former prosecutor had met Giuliani “to record a documentary”, without providing details.
A journalist with right-wing OANN channel Chanel Rion posted photos of the two together on Twitter on Thursday, saying she interviewed Lutsenko in Budapest.
Giuliani has approached former and current Ukrainian officials over the past year to aid Trump’s effort to find dirt on Democrats ahead of the 2020 presidential election.