A Ukrainian artist who made headlines with a giant portrait of Russia's Vladimir Putin in bullet shells has now taken aim at her own President Petro Poroshenko - using wrappers from around 20 kilograms of sweets to craft his image.

Poroshenko, who amassed a vast fortune in the chocolate business and came to power after a 2014 popular uprising forced his predecessor from office, is facing an uphill re-election battle this weekend.

"There's a feeling that they offered us a sweet but they didn't give it to us," said artist Daria Marchenko of the unrealised hopes of the revolution, five years on.

"So what do we have? We have an empty wrapper - the remnants," the 37-year-old said, gesturing at the large-scale artwork she has named "The Face of Corruption".

Poroshenko's glowering image, formed from the multicoloured wrappers of his Roshen brand of confectionery and framed with bullet shells collected from the separatist conflict in Ukraine's east, covers half a wall of Marchenko's Kiev flat.

"It's also a symbol of business... business is our president's priority."

Poroshenko came to power promising to tackle graft and shut down the conflict with Russian-backed rebels in the east.

Despite some reforms, after his first term corruption is still endemic and the ongoing conflict has cost some 13,000 lives.

Marchenko, along with co-creator Daniel Green, took part in the protests that forced pro-Russian Viktor Yanukovych out of office.

But she says that, after they created a portrait of Putin made up of more than 5,000 bullet shells in 2015 as a comment on his role in the Ukraine conflict, the pair received threats and decided to leave the country.

Working in the US, they attracted attention with another large-scale work -- this time of President Donald Trump, made from coins and poker chips.

Marchenko says she decided to return to Ukraine this year but Green remains abroad.

On Sunday, Ukrainians will vote in the first round of an unpredictable election that polls suggest may see Poroshenko booted from office.

Comedian Volodymyr Zelensky, whose sole political experience is playing the president in a popular TV show, is well ahead of his rivals, according to surveys.

But analysts say his largely young support base may not turn out to vote.

Marchenko, who says she will take part, is keeping her options surprisingly open.

"I can't say that I haven't considered Poroshenko. That's the situation we're in in the country - we're choosing from a number of evils."