Leader of Greek conservative New Democracy party Vangelis Meimarakis speaks to Greek President Prokopis Pavlopoulos (not pictured) during their meeting in the presidential palace in Athens, Greece, August 21, 2015. [Photo/Agencies]

ATHENS - Greek conservative leader Vangelis Meimarakis will seek an alliance with his main leftist rivals first if he wins this month's election, insisting that the country must not miss the "last chance" to pull itself out of a seven-year crisis.

In an interview with Reuters, the 61-year-old political veteran said his New Democracy party would turn to other pro-European groups if Syriza - the leftist party that led Greece for seven turbulent months this year - rejected his advances.

Syriza forced the election last month when its leader Alexis Tsipras resigned as prime minister, hoping to end a party rebellion over Greece's new bailout deal and return to power with an outright parliamentary majority.

But New Democracy, which lost power only in January, has surprised everyone with the strength of its campaign. Opinion polls put it neck-and-neck with Syriza, meaning the election on Sept. 20 is unlikely to produce an outright winner. A coalition government will therefore have to be cobbled together to ensure Greece is not forced into a disruptive new round of elections.

"The first party that I would turn to would be the one that ranked second," said Meimarakis, who became interim New Democracy leader in July after former prime minister Antonis Samaras resigned.

"If the second party does not want to join in, I will turn to the parties which believe in the country's European course and with which we can at least agree on a plan of a viable government, hopefully a four-year term one."

Meimarakis was referring to Syriza, which in negotiating the 86 billion euro ($97 billion) bailout with the euro zone and IMF was forced to ditch its election promises to end austerity.

The polls suggest the election will be a largely two-horse race, meaning that if New Democracy wins, Syriza is almost certain to be the second party in the next parliament. Support for each party fluctuates around the 25 percent level.

Greece needs a stable government to implement its side of the bailout deal to keep the country from lurching back towards bankruptcy and an exit from the euro, as it did this summer.

However, Syriza has so far spurned overtures from New Democracy, calling it part of an establishment responsible for the economic malaise. Tsipras says he is still hoping for an outright victory and a mandate to implement the austerity policies demanded by the creditors which have split his party.

Other pro-euro parties Meimarakis could turn to include the Socialist PASOK and centrist To Potami. The right-wing Independent Greeks' party - Tsipras's former coalition ally - however, has suggested it would prefer to team up with Syriza again.

Since sliding into crisis in 2008-2009, Greece has held four parliamentary elections and had seven governments. In 2012 it held two elections in successive months to break a political deadlock.

But a repeat election this time would plunge the country into political instability, said Meimarakis, a former speaker of parliament.

"This is the country's last chance," he said. "I am mature. I'm ready, with a plan, with the party's top brass and a united parliamentary group, to pull the country out of the crisis."

Meimarakis accused Tsipras of scaring away investors during his brief time in power, when the banks were closed for three weeks, capital controls were imposed and several privatisation deals stalled.

Greece should unblock big infrastructure projects halted under the last government and sign up to more investment. "Our first aim is to restore confidence in the country," he said.