* Nikkei briefly falls to six-week low
* Nikkei has fallen 8.7 pct from this month's 27-year peak
* All but three of Topix's 33 subsectors trade in the red
By Daniel Leussink
TOKYO, Oct 19 (Reuters) - Japan's Nikkei fell on Friday, tracking broader losses in global equities markets and heading for its third straight week of decline.
The Nikkei share average at one stage dropped almost 2 percent to hit a six-week low of 22,212.57. Halfway through the morning session, it was down 1.48 percent at 22,323.74.
Japan's benchmark index has given up around 8.7 percent since its 27-year peak hit on Oct. 2, as worries over Italy's 2019 budget and growth concerns in China weigh on market sentiment globally. Investors also await November congressional elections in the United States.
On Friday, stocks in Asia weakened as global sentiment soured on issues ranging from trade worries, Italy's 2019 budget, higher U.S. interest rates and growth concerns in China.
"The recent price action in Japanese equities suggests the domestic market is quite sensitive to what's happening in the U.S.," said Shusuke Yamada, currency and equity strategist at Bank of America Merrill Lynch.
"In general, there is a certain degree of uncertainty from external risks," he said.
While all but three of the Topix's 33 subsectors were in the red, machinery-related stocks underperformed.
Shares of construction equipment maker Komatsu sank 4.2 percent, Kubota Corp lost 2.5 percent and Nabtesco Corp slipped 3.1 percent.
Index-heavyweights such as SoftBank Corp and Nintendo declined, falling 2.7 percent and 3.6 percent, respectively.
Exporters fell after the yen strengthened overnight towards a one-month peak versus the dollar reached on Monday.
Sony Corp lost 2.7 percent and Panasonic Corp gave up 1.1 percent.
"There is a rotation into domestic and somewhat defensive names recently," Yamada said.
"This year, we've seen exporters weaker, and especially those exposed to China, so the machinery sector has been weaker," he said.
Car makers also fell but losses were somewhat limited by a media report on Thursday that Japan is considering a temporary tax break for car purchases next year.
Toyota Motor Corp dipped 1.0 percent, Nissan Motor Co was down 0.6 percent and Honda Motor Co lost 1.4 percent.
The broader Topix declined 1.3 percent to 1,682.52.
Editing by Sam Holmes