Japan's benchmark Nikkei index hit a fresh 15-year high on Thursday, leading most Asian shares higher as oil prices rebounded and boosted shares of energy firms.

In Japan, the benchmark Nikkei 225 closed up 1.08% at 18,785.79 points, marking its sixth day of gains across seven sessions.

Hong Kong's Hang Seng closed up 0.5% at 24,902.06.

The Shanghai Composite index closed 2.2% higher at 3,298.36.

One of Asia's largest insurers, the Hong-Kong listed AIA Group, posted better than expected earnings because of growth in its operations across China.

AIA is the former Asian arm of the US insurance giant AIG.

"Our performance is a clear reflection of the strength of AIA's business model, the determined execution of our proven growth strategy and our position as the leading insurer exclusively focused on the Asia-Pacific region," said the firm's chief executive Mark Tucker.

The company listed in 2010 and is the biggest international life insurance player in China.

Elsewhere in Asia

Australia's benchmark S&P/ASX 200 closed down 0.61% at 5,908.49 following official numbers that showed Australian business investment had slipped to a three-year low in the fourth quarter of 2014.

However, Australia's national carrier Qantas reported its best half-year profit in four years, as turnaround plans came to fruition.

Shares in the Sydney-listed airline rose more than 6% following the news, before closing up 1.4%.

In Singapore, share trading was halted for one of Asia's biggest commodity-trading firms, Noble, after a little-known research firm released its second report raising questions about the company's books.

Iceberg Research said Noble had overstated the value of the commodities it holds by as much as $3.8bn (£2.4bn).

The commodities giant is set to announce its latest earnings numbers later on Thursday.

Analysts said Iceberg's report had a strong sense of activism in its intent.

"Again, this report made several comparisons between Noble's accounting procedures with that of the failed Enron," said CMC markets analysts Nicholas Teo.

He said the report was "as sensational - even ominous - as the first", but that while Noble's management had refuted claims made in the first report, they had "remained rather quiet through this episode".

In Korea, the Kospi share index closed up 0.13% at 1,993.08.