New Zealand stocks were flat with a positive bias as markets returned from a holiday on Tuesday, with the US poll elections dominating investor chatter across the globe.

The S&P/NZX 50 Index was little changed at 12,783.36.

The index has gained past 8% year-to-date.

Asian shares traded mixed, with the Shanghai SSE down 0.7%, while Japan's Nikkei 225 was up 0.5%. Hong Kong's Hang Seng was little changed. With only almost a week left, global markets are all eyes on the US presidential polls, with several surveys showing a tight race between Vice President Kamala Harris and former president Donald Trump.

In domestic news, the country's seasonally adjusted filled jobs across all industries were little changed at 2.4 million in September compared with August, Stats NZ data showed.

Meanwhile, New Zealand's official reserve assets dropped to NZ$32.54 billion in September from NZ$32.57 billion in August, according to the Reserve Bank of New Zealand.

In corporate news, Serko (NZE:SKO, ASX:SKO) soared over 15% after it bared plans to acquire Nasdaq-listed Sabre's business travel management platform, GetThere, for $12 million as part of its North American expansion.

Fonterra Co-operative Group (NZE:FCG) fell more than 2% after it unveiled an offering of up to NZ$250 million of unsubordinated, unsecured five-year fixed-rate bonds due 2029.