Sony Corp said on Tuesday it was not certain when it could fully restore PlayStation Network videogame services in Japan, Hong Kong and South Korea, five weeks after a massive network security breach forced the company to shut them down.

Sony's delayed response to the attack and a series of other network security problems has sparked criticism from governments and experts and threatens an online strategy meant to unite the sprawling electronics conglomerate.

Full services in the rest of the world will be restored by the end of the week, Sony said in a statement, just missing the initial target date of May 31.

The theft of information on 77 million PlayStation accounts and millions more from a PC-based gaming network angered many users, some of whom have said they would switch to rival Microsoft's Xbox Live service.

A spokesman for Sony Computer Entertainment, the company's games unit, said the delay in restoring services in Japan was due to the need to comply with government guidance on information security, but he declined to specify reasons for the delay in other parts of Asia.

Japan, South Korea and Hong Kong together account for less than 10 percent of the PlayStation Network user accounts affected, but the news sparked angry comments.

Why are you so slow dealing with Japan....? Is Sony really a Japanese company? fumed an anonymous post on Yahoo Japan's news site.

Sony's shares were up 1.4 percent by 1 a.m. EDT in line with the broader Nikkei index up 1.7 percent. Sony's shares have slumped about 10 percent since it revealed the attack.

Sony has said it expects the hacking to drag down operating profit by 14 billion yen ($172 million) in the current financial year, including costs for boosting security measures.

PlayStation Network users in Japan have already had online play services restored but do not yet have access to some other services, such as the PlayStation Store, where they can buy games.

We have been conducting additional testing and further security verification of our commerce functions in order to bring the PlayStation Network completely back online so that our fans can again enjoy the first class entertainment experience they have come to love, Kazuo Hirai, Sony's No. 2, said in the statement.

We appreciate the patience and support shown during this time.

Sony said it would announce details for Japan, Hong Kong and South Korea as they became available.

Sony's officials are due to testify before U.S. lawmakers at a hearing on data security in Washington on June 2.

Last week, Japan's Ministry of Economy, Trade and Industry criticized Sony for what it said was insufficient supervision and for the delay between the company discovering suspicious activity on its networks and informing customers and authorities.

The ministry issued guidance on improvements to be made by the company, including better communications between the company's divisions and more supervision of contractors.

(Editing by Michael Watson and Anshuman Daga)

Japan South Korea Sony