* Yen weakens on Abe's ruling bloc victory in Sunday's election
* Fresh records on Wall Street also underpin sentiment
By Lisa Twaronite
TOKYO, Oct 23 (Reuters) - Japan's Nikkei share average notched 21-year highs on Monday to rise for a record 15th straight session, lifted by a weaker yen after Prime Minister Shinzo Abe's coalition scored a resounding election victory on Sunday.
The Nikkei ended up 1.1 percent at 21,696.65.
The index gained 1.4 percent last week, making its sixth straight weekly gain and its longest weekly winning streak in a year, leaving investors to ponder how long it might continue.
"While upward momentum is apparently strong, it would not be unusual for short-term profit-taking to emerge," said Yutaka Miura, a senior technical analyst at Mizuho Securities.
Abe's coalition kept its two-thirds "super majority" in the lower house, reassuring investors that his "Abenomics" economic reforms would continue, including the Bank of Japan's easy monetary policy, which has resulted in a weaker yen, benefiting exporters.
"It would be particularly positive if this very strong political position that Abe has re-established allows him to push for further radical policy - that would be a bonus," said Stefan Worrall, director of Japan equity sales at Credit Suisse in Tokyo.
The market's attention will now shift from to company earnings, he said, which could underscore Japan's recovery and pave the way for more gains as long as external factors are favourable.
U.S. stocks hit record closing highs on Friday and the S&P 500 posted its sixth week of gains after the U.S. Senate passed a budget resolution, lifting hopes that President Donald Trump's tax-cut plan may move forward.
Fuelled by Abe's victory and hopes of Trump's tax reform, the dollar rose to three-month highs above the 114-yen level, though it later fell back below it.
The weaker yen gave many exporter shares a lift, with Tokyo Electron rising 2.5 percent and Murata Manufacturing adding 1.1 percent.
The insurance sector gained 1.4 percent, as T&D Holdings rose 1.5 percent.
Banks also gained, with the banking subindex up 1.1 percent. Mitsubishi UFJ Financial Group rose 1.6 percent.
Toshiba shares skidded 1.2 percent after the company said it expects to post a net loss of 110 billon yen for the fiscal year through March, compared with its previous forecast for a net profit of 230 billion yen.
Shares of Kobe Steel Ltd edged down 0.1 percent.
On Friday, the embattled steelmaker said it had lost some customers because of widespread data falsification that had extended to its mainstream steel sheet business. It also admitted it had violated statutory standards set by the industry ministry.
The broader Topix marked 10-year peaks and ended 0.8 percent higher at 1,745.25, while the JPX-Nikkei Index 400 gained 0.9 percent to 15,471.27. (Reporting by Lisa Twaronite; Editing by Simon Cameron-Moore and Eric Meijer)