* Nikkei has dropped 9.2 pct on month
* Surging yen, Brexit weigh heavily
* Mitsubishi Heavy soars on report about subsidiary's plant plan
By Ayai Tomisawa
TOKYO, June 30 (Reuters) - Japan's Nikkei share average rose for a fourth day on Thursday, helped by bargain hunting in recently battered stocks, but the benchmark index looked set for its biggest monthly drop in more than four years as a surging yen pressures exporters.
The Nikkei gained 0.7 percent to 15,671.89 points by mid-morning.
It has now recouped more than half of its losses since Friday's global market rout sparked by the Britain's vote to leave the European Union.
But in June, the Nikkei has tumbled 9.2 percent, the biggest monthly drop since May 2012.
"The market panicked at first (about Brexit), but it doesn't look like it is spreading into a financial crisis or something serious at least at this moment," said Hikaru Sato, senior technical analyst at Daiwa Securities.
He said that expectations that major central banks will take steps to counter fallout from have helped calm investors.
"Not that we get real damage now, so people are buying back," Sato said.
Exporters gained ground, with Toyota Motor Corp rising 0.6 percent and Honda Motor Co adding 1.3 percent.
The dollar edged down 0.1 percent to 102.72 yen, well above its 2-1/2-year low of 99.00 hit in volatile trade on Friday.
Financials also advanced, with Sumitomo Mitsui Financial Group rising 0.7 percent, Mizuho Financial Group gaining 0.5 percent and Nomura Holdings adding 1.3 percent.
Mitsubishi Heavy Industries jumped more than 5 percent in heavy trade after the Nikkei business daily reported that subsidiary Mitsubishi Aircraft plans to launch a mass-production plant for its regional passenger jet.
The broader Topix gained 0.5 percent to 1,254.18 and the JPX-Nikkei Index 400 advanced 0.5 percent to 11,323.08.
Editing by Kim Coghill