* STOXX 600 rises 0.55 pct
* Financial stocks among top gainers
* Insurance sector still up after Monday rally (Adds closing prices)
LONDON, Sept 12 (Reuters) - European shares rose to a five-week high on Tuesday, extending the relief bounce seen in the previous session as worries about Hurricane Irma and North Korea's nuclear standoff eased.
All major trading centers and most sectors ended in positive territory as the pan-European STOXX 600 gained 0.55 percent, although some investors questioned how sustainable current markets levels are.
"Whether that equity reaction is Panglossian complacency or a sign of wonderful underlying fundamentals remains open to question," ING wrote, adding that "even Category 5 storms can now be added to the list of things that 'Don't Really Matter'."
Financial stocks were yet again among the top performers, with banks and financial services up 1.6 and 1.1 percent respectively.
Insurance firms, which fueled Europe's rise on Monday with a roughly 2 percent jump, were again in positive territory, edging up 0.8 percent.
"The structure of today's open is typically 'risk-on'," said Pierre Martin, a senior sales trader at Saxo Bank, noting that the positive trend for banking stocks or automobile shares showed investors' moods were off geopolitical and climate worries and back to more positive corporate and macroeconomic news.
Volkswagen rose 1.9 percent after announcing a 20 billion euro plan to develop zero-emission vehicles and other constructors were also gaining ground, such as Peugeot which topped France's blue chip CAC 40 index with a 3.8 percent rise.
Novartis gained 1.3 percent as it reported that its biosimilar rituximab to treat blood cancers and immunological diseases such as rheumatoid arthritis was accepted for review by the U.S. Food and Drug Administration (FDA).
Among losers, French veterinarian pharmaceutical company Virbac sank 16.3 percent after cutting its full-year outlook.
British home builders were also under pressure with Taylor Wimpey losing 1.4 percent and Barrat Development 1.7 percent after a report highlighted risks to the sector, a trader said. (Additional reporting by Danilo Masoni; Editing by Alison Williams)