By Thomas Escritt

AMSTERDAM (Reuters) - The Dutch Socialist Party, campaigning for tax hikes for the rich and looser budget deficit targets for Europe, led in a rash of opinion polls a month ahead of a parliamentary election.

The hard-left movement was seen winning as many as 37 seats in the 150-seat assembly - a result that would leave it the biggest party in parliament but needing an alliance with at least two other groups to take power.

The emergence of the Socialists in a country which has long been Germany's leading ally in demanding fiscal discipline in the euro zone could have broader implications as Europe battles to solve the debt crisis in the indebted South.

The current coalition government of acting prime minister Mark Rutte has harshly criticized southern countries for their budget laxity.

But with the Dutch economy growing only 0.2 percent in the second quarter, consumer confidence low and unemployment creeping up, polls suggest many voters have been attracted by a party which promises to maintain the country's generous welfare state.

The Socialist Party, which started as a tiny Maoist group in the 1970s, would win 37 seats - more than double the 15 it holds now - according to a poll released on Sunday by De Hond. That poll saw Rutte's Liberals (VVD) winning 31 seats.

The two parties were closer in a poll by TNS Nipo on Tuesday which had the Socialists winning 34 seats and the Liberals 33.

Analysts predict it could take weeks or even months for the Socialists to form a new government. The party, which has never been in power before, would risk alienating its voters if it watered down its plans to accommodate potential partners in government.

Shortly after the last Liberal-Christian Democrat government collapsed in April, those two parties banded together with three opposition parties to pass an emergency budget. However, most polls show that even these five parties together would not have a parliamentary majority.

(Reporting by Thomas Escritt; Editing by Andrew Heavens)