Thousands of South Korean ice hockey fans chanted "we are one" as the joint Korean women's team played their first pre-Winter Olympics game against powerhouse Sweden.

About 3,000 fans packed the Seonhak International Ice Rink in Incheon on Sunday, loudly showing their excitement throughout the match despite a 3-1 loss to the Swedes.

North and South Korea agreed last month to field a combined women's ice hockey team and march together under one flag in Pyeongchang, South Korea during the February 9-25 Winter Games, after a new round of talks as cross-border relations continue to improve.

Fans waved miniature white-and-blue flags depicting a map of a unified Korean Peninsula, the same design on the players' uniforms.

The North and South Korean hockey players only began practicing together about a week ago as a combined team.

Critics noted some South Korean players would lose their opportunity to participate in the Olympics because of the addition of the North Koreans, but the team's coach downplayed those concerns.

"As a coach, it is hard to tell some of your players that you have been with for a quite a long time that they are not going be able to play, but the whole situation is out of our control. So we are trying to make the best out of it," Canadian head coach Sarah Murray told a news conference after the game.

Pak Chol-ho, the team's North Korean coach, said the Koreas "can do anything if they do things as one".

Hopes remain high the unified women's hockey team could further lessen the tensions over the past year that raised the spectre of war on the divided peninsula.

US President Donald Trump has threatened to "totally destroy" North Korea if it threatens its neighbours with nuclear weapons and intercontinental ballistic missiles (ICBMs).

Pyongyang has said it could now attack anywhere in the United States with its latest ICBM.

Some conservative groups held protests and tore up a North Korean flag ahead of the hockey game calling for North Korean leader Kim Jong-un to step down.

"The unified team is politically contaminated," said Cho Young-hwan, 58.

"The Olympics offered an opportunity for the North to publicise its propaganda and create a conflict within South Korea. In this situation, how can the two Koreas be unified?"