With no party seen as holding a decisive lead the election is likely to be followed lengthy coalition talks, although whichever party wins on Sunday will have the first attempt at forming a government.
Opinion polls show her Social Democrats, the biggest party in the outgoing coalition government, in a dead heat with the rightist National Coalition Party and the nationalist Finns Party, with all three seen winning some 18.7-19.8% of ballots.
It has promised to curb spending and stop the rise of public debt, which has reached just over 70% of GDP since Marin took office in 2019.
"It's been going on for 30 years - more debt, debt, debt - and good services, fine, but on borrowed money."
The Finns Party, too, calls for austerity but its main goal is to reduce what its leader Riikka Purra has called "harmful" immigration from developing countries outside the European Union.