BRUSSELS, Feb 14 (Reuters) - NATO Secretary-General Jens Stoltenberg said on Tuesday it was more important that Finland and Sweden's applications to join the alliance were ratified quickly than together.

The two countries applied to join NATO following Russia's invasion of Ukraine in February last year and their membership bids have been ratified by all allies except Hungary and Turkey.

Turkey is widely seen as the main hold-up and Turkish President Tayyip Erdogan has indicated his country could ratify Finland's application while not going ahead with Sweden's.

Western officials have said they would prefer both countries to join NATO together, partly because it would be easier to integrate them at the same time into NATO's military structures.

But Stoltenberg, speaking before a meeting of NATO defence ministers at alliance headquarters in Brussels, suggested that was a secondary consideration.

"The main question is not whether Finland and Sweden are ratified together. The main question is that they are both ratified as full members as soon as possible," he told reporters.

"I'm confident that both will be full members and I'm working hard to get both ratified as soon as possible."

Stoltenberg stressed Sweden and Finland had already come much closer to NATO in recent months. He also noted that all NATO members had approved the two countries' invitations to join the alliance.

Erdogan, however, said earlier this month that Turkey looks positively on Finland's NATO bid but does not support Sweden's.

Ankara has demanded that both countries take a tougher line against the Kurdistan Workers' Party (PKK), which is considered a terrorist group by Turkey and the European Union, and another group it blames for a 2016 coup attempt.

Finnish parliamentary groups said on Friday they may ratify NATO's founding treaties in the coming weeks, a step that could lead to Helsinki proceeding with membership ahead of Sweden.