* Investors wary ahead of U.S. jobs data later on Friday
* MS&AD Insurance rises after it takes stake in UK insurer
TOKYO Oct 6 (Reuters) - Japan's Nikkei share average scaled a fresh two-year peak on Friday and posted its fourth straight weekly gain, buoyed by the impact of a weaker currency as well as record highs on Wall Street.
The Nikkei ended 0.3 percent higher at 20,690.71 points, after probing its highest levels since August 2015. For the week, it added 1.6 percent.
On Thursday, the S&P 500 posted its sixth straight record high close on Thursday, its longest run since 1997, as investors cheered increased prospects for a tax overhaul with Congress moving closer to agreement on a budget resolution.
A weaker currency also gave Japanese shares a lift. The dollar edged up 0.1 percent on Friday to 112.98.
"The Nikkei is getting a lift from U.S. stocks gains, and hopes that tax reform will be implemented, though it remains to be seen whether the U.S. momentum can continue," said Norihiro Fujito, a senior investment strategist at Mitsubishi UFJ Morgan Stanley Securities.
"On the domestic side, there is Japan's election this month, and there is not yet a consensus on a likely outcome and the market impact," he said.
Prime Minister Shinzo Abe last week called a snap election for Oct. 22, in a bid to maintain his conservative Liberal Democratic Party-led coalition's majority in the lower house. But support is growing for a new party formed by Tokyo's popular governor, Yuriko Koike.
Investors were also wary ahead of key U.S. employment data later in the global session, as well as continuing tensions surrounding North Korea.
A week ago, Japan's defense minister expressed concerns about a possible provocation from North Korea on Oct. 10, when Japan begins campaigns for its upcoming lower house election - a date that will coincide with one of Pyongyang's main anniversaries.
Shares of Japan's MS&AD Insurance Group Holdings were up 1.6 percent, after it said on Friday it had agreed with Swiss Re AG to invest 800 million pounds ($1.05 billion) to take a stake of up to 15 percent in UK-based ReAssure Jersey One Ltd.
Toshiba Corp shares rose 1.0 percent.
U.S. private equity firm Bain Capital LP on Thursday said it aims to list Toshiba's chip unit on the Tokyo Stock Exchange within three years, to cash in its investment after leading an $18 billion acquisition of the business.
Toshiba aims to complete the sale by the end of its fiscal year in March.
The broader Topix gained 0.3 percent to 1,687.16, while the JPX-Nikkei Index 400 rose 0.2 percent to 14,891.99. (Reporting by Lisa Twaronite and Ayai Tomisawa; Editing by Kim Coghill)