China's troubled property sector has seen its first default outside the mainland, with developer Kaisa unable to pay interest on its Hong Kong-listed bonds, but analysts said an immediate crisis is unlikely despite market woes.

Kaisa Group Holdings Ltd, based in the boom town of Shenzhen that borders Hong Kong, failed to pay interest totalling $52 million on 2017 and 2018 notes due last month. It confirmed the default on Monday when a 30-day grace period expired.

Analysts said Kaisa's problems were unusual and unlikely to occur in other firms.

"It is an isolated event," Kalai Pillay, head of Asia-Pacific industrial ratings at Fitch Ratings in Singapore, told AFP on Tuesday. "This company had specific issues."

Last November Shenzhen authorities blocked sales of Kaisa's property units, a move allegedly linked to a graft investigation into the city's former security chief Jiang Zunyu, Bloomberg News reported.

The block was allegedly meant to pressure company chairman Kwok Ying Shing into cooperating with the probe but left the company with a severe shortage of funds.

Pillay added that while other defaults cannot be ruled out, any that occur would be "isolated" and pose no "systemic" risk.

Chinese developers, particularly the larger ones, have actually become more transparent over the past five years or so because they rely heavily on the offshore bond market for funding to buy land.

They cannot borrow domestically for that purpose under Chinese rules, according to Pillay.

"In many ways the use of offshore bond funding by Chinese developers has resulted in a significantly improved governance structure in the industry," he said.

Moody's Investors Service said Kaisa's default would undermine investor confidence.

"But... the overall refinancing risk for the sector remains manageable for 2015," it said in a note on Tuesday.

China's real estate market has been weakening since early 2013 and has continued to contract despite easing policies as overall economic growth slows.

Growth weakened to a post-financial crisis low in the first quarter after the country last year posted its slowest annual expansion since 1990.

Meanwhile, home prices in major Chinese cities have declined in 10 out of the past 11 months, a survey by the China Index Academy showed last month, raising concerns over the profitability of developers.

Christopher Yip, Standard & Poor's director of corporate ratings in the Asia-Pacific region, agreed that the Kaisa default was an "unusual case", but warned that the risk of more property defaults has increased over the last year.

"Other defaults or potential defaults that might come out from the property sector might more be due to the weakening fundamentals of the property developers themselves rather than external factors," he said.

The margins and profitability for property developers have been weakening while some companies continued to borrow for aggressive expansion, he added.

"Once these debts become due and weigh on their short-term maturity, their liquidity position will also deteriorate. So we expect default risks could go up in general for the sector," he said.

Other analysts were less worried about the overall market, calling the downturn cyclical.

Pillay attributed the current woes to overbuilding in 2013.

"You need a period of consolidation to absorb that excess inventory," he said.

"The longer-term trend for China is that urbanisation will continue to be an important government agenda -- they committed to do it."