With 97% of votes in the Dutch election counted, the governing Christian Democrats are ahead, having taken 41 seats, but remain short of a majority.
The Socialists were big winners, more than doubling their seats
Prime Minister Jan Peter Balkenende has claimed victory, saying his party is again the biggest group in parliament.
If confirmed, Mr Balkenende will get the first chance to form a coalition, but the process could be lengthy.
According to the partial results, the opposition Labour party remains the second biggest party with 32 seats.
The Dutch are split between parties tough on immigration and pro-business, and left-leaning parties with a softer approach, correspondents say.
Neither the right nor left blocs were on course to win the 76 seats needed to control the 150-seat parliament.
The Christian Democrats' (CDA) current coalition partners, the Liberals (VVD), won 22 seats, meaning the CDA would need to include several more parties to reach a working majority.
Nonetheless CDA members have been celebrating the result.
"We are the biggest party again... the effort of four years of struggle has been rewarded and that makes me proud, " Mr Balkenende told supporters.
"It is a fantastic result because in March in the local elections we won just 28 or 29 seats, so 41 is a great achievement," CDA MP Coskun Coruz told the BBC.
The BBC's Sam Wilson in The Hague says that the celebratory mood at the CDA's party headquarters was in stark contrast to the atmosphere at the Labour Party's offices, where many are unhappy at the loss of many seats to the Socialists.
According to the latest figures from the Dutch Electoral Council, the Socialists were the biggest winners of the night, now occupy third place with 26 seats.
"We expected to double our seats but this is absolutely fantastic. I am proud the Netherlands wants to move left," said Socialist Party MP Agnes Kant.
The other big winner was the anti-immigration Party for Freedom, PVV, led by Geert Wilders, which took 9 seats.
The Party for the Animals has won parliamentary representation
The Christian Union won six seats, as did the Green party, while the Party for Animals is likely to win two seats, a result which would make it the first animal rights party in a European parliament.
The split vote will make any coalition hard to pin together, our correspondent says, and people are already talking about protracted coalition talks, or even a "monster" coalition involving right and left.
"It's chaos. It is extremely difficult to distil a government out of these results," said Finance Minister Gerritt Zalm from the VVD.
"The jigsaw can still be laid in many different ways," said a Labour candidate Nebahat Albayrak.
The CDA-led governing coalition collapsed in June after a row over its handling of the disputed citizenship of a Somali-born Dutch politician.
Some 12 million people were eligible to elect the 150-member lower house parliament. The MPs are elected for a four-year period by proportional representation.
In a live TV debate on the eve of the election, the party leaders focused mainly on welfare reforms rather than immigration.
The immigration issue had gripped Dutch politics since the high-profile murders of two prominent campaigners against Muslim extremism - independent politician Pim Fortuyn and film-maker Theo van Gogh.
On Friday, the cabinet backed a proposal to ban face-covering clothing, including the burqa worn by some Muslim women.
The main parties have both embraced pro-integration policies - a departure from the Dutch tradition of multiculturalism.
Mr Balkenende has also been claiming credit for a strong economic recovery in the country in the past few years.
Labour leader Wouter Bos hoped his party will be able to successfully challenge the CDA or at least force its way into a grand coalition.