TOKYO, March 26 (Reuters) - Japan's Nikkei share average dropped to a six-month low on Monday morning while the yen rose to near a 16-month peak, on persistent worries about a global trade war, although some stocks were in demand before they go ex-dividend this week.

The Nikkei fell 0.9 percent to 20,439.98 in midmorning trade after hitting a low of 20,347.49, the weakest since late September.

The dollar traded at 104.835 yen after falling to 104.560, its lowest since November 2016.

U.S. President Donald Trump signed a memorandum last week that could impose tariffs on up to $60 billion of imports from China, although the measures have a 30-day consultation period before they take effect.

However, with the business year-end looming on March 31 for a majority of listed companies, some stocks were bought before they go ex-dividend on Tuesday.

"Although buying by investors hunting for dividends should support the market's call somewhat, we are eyeing much lower levels for the Nikkei going beyond," said Yutaka Miura, a senior technical analyst at Mizuho Securities, adding that he expects a support level of around 19,500 over the next month.

Tokyo stocks also continue to be pressured by a cronyism scandal that has gripped the country and sparked a political crisis for Prime Minister Shinzo Abe.

Former Japanese tax agency chief Nobuhisa Sagawa, a key figure in the scandal, will be summoned to testify in parliament on March 27, a ruling party source told Reuters.

Semiconductor related stocks tumbled, with high-purity silicon maker Sumco shedding 3.3 percent and Tokyo Electron falling 2.8 percent.

Electronic components makers also lost ground, with Alps Electric falling 2.2 percent and Murata Manufacturing shedding 1.9 percent.

Shippers were sold, with Mitsui OSK Lines and Kawasaki Kisen both giving up around 2.0 percent.

Drugmakers outperformed. Astellas Pharma rose 1.2 percent and Eisai gained 1.1 percent.

The broader Topix fell 0.7 percent to 1,653.55. (Reporting by Ayai Tomisawa; Editing by Himani Sarkar)