(Updates with comments, stocks on the move)
MELBOURNE, Jan 25 (Reuters) - Australian shares gained 0.3 percent on Friday, climbing for an eighth straight session and touching a 21-month high, boosted by solid China factory data and Japanese stimulus measures.
For the week, the market was on track to post a gain of 1.1 percent. The benchmark has risen 3.8 percent so far in January.
"I think the market is certainly on a roll," said Lonsec senior client adviser Michael Heffernan.
"The U.S. debt ceiling has been pushed out, Japan is stimulating their economy and Europe seems to have digested their debt crisis. There aren't a lot of negatives at the moment," he said.
The benchmark S&P/ASX 200 index advanced 15.5 points to 4,824.8 by 0010 GMT, with volumes heavy in options-related trading. It was the best intraday level since May 2, 2011.
The index closed 0.5 percent higher on Thursday.
Australian markets will be closed on Monday for the Australia Day holiday.
New Zealand's benchmark NZX 50 index reversed early losses and was up 0.1 percent at 4,195.9.
* Shares in retailer Specialty Fashion Group surged by more than one-third after the company forecast its first-half net profit would nearly triple - a rare earnings upgrade for the battered retail sector.
The owner of Katies and Millers chains said cost cutting and reduced cotton prices would help to lift profit, on just a 2 percent rise in sales. The company is due to report results on Feb. 18. The shares traded up 34.3 percent at A$0.94.
* Underwear maker and retailer Pacific Brands, maker of Bonds, jumped 5.1 percent to A$0.657.
* Shares in Karoon Gas Australia Ltd leapt 16 percent after it said it had found oil at its Kangaroo-1 well off the coast of Brazil.
Karoon shares touched a high of A$6.24 and last traded up 15 percent at A$6.21.
* Healthcare firm ResMed , which makes products to treat sleep disorders, saw its shares jump 5.1 percent to A$4.50.
It reported second-quarter profits jumped 24 percent, with revenue up 13 percent on U.S. and European demand. The stock has gained 70 percent over the past 12 months.
2340 GMT (Reporting by Victoria Thieberger; Editing by Edmund Klamann)