Both the Independence Party and the Pirate Party have so far ruled out working together, though this could change during negotiations in the days to come.
With roughly 40 percent of overall votes counted, the centre-right Independence Party emerged as the winner with 30 percent, followed by the Left-Greens with 16 percent and the Pirate Party third at almost 14 percent.
"Our internal predictions showed 10 to 15 percent so this (the first results) is at the top of the range. We knew that we would never get 30 percent," Pirate Party leader and a published poet Birgitta Jonsdottir told Reuters at an election wake at the harbour of Reykjavik.
Neither the two centre-right parties currently in government nor the four opposition parties led by the Pirates looked able to win a majority.
Three political scientists that Reuters talked to said it was very difficult to predict what kind of constellation would emerge when all the votes are counted.
In a tight race, the newly established Vidreisn, or Reform Party, could become kingmaker. The pro-European, liberal party has not yet taken sides.
While the Independence Party clearly emerged as the top party, its senior coalition partner, the Progressive Party, only got around 10 percent with around 32 percent of votes counted.
The Progressive Party was hurt badly when Sigmundur David Gunnlaugsson resigned as prime minister in April after documents leaked from a Panamanian law firm linked him to an offshore company that held millions of dollars in debt from failed Icelandic banks.
It was still too early to say, however, which party or parties would take power over the small island, as President Gudni Johannesson has yet to officially hand the mandate to the party that will be tasked with forming the next government.
"I cannot deny that if the results will be this way... that it would be natural that we are a leading party in the next government," said party leader Bjarni Benediktsson.
The Independence Party has promised to lower taxes and keep the economic recovery on track.
Fuelled by a tourism boom, economic growth has recovered since the 2008 banking crisis and is expected to hit 4.3 percent this year.