This is probably in response to this article.
It is scheduled that BIGBANG will promote in Japan in May and June but fans raised their concern about their Japan tour. Regarding that, YG Entertainment has the same concern as fans.

Ever since the earthquake, YG has taken into consideration whether to postpone BIGBANG's Japan tour date. Since the situation in Japan is still not stable currently, the schedule is still not confirmed yet although we have already communicated with the company in Japan for a few times already.

Like other Korean singers who have advanced into the Japanese market, the final decision whether we will still carry out the same schedule depends on our contract with the company in Japan since the company has the authority to do so.

In fact, this problem is not only faced by YG and BIGBANG since in May, other groups like ‘SNSD’ and ‘2PM’ have also planned to do their activities in Japan. These days, concerning the Japan’s situation, BIGBANG would rather proceed their concerts and donate some of their earnings to the 2700 victims of the affected areas in Japan, our VIP fan club in Japan also planned to help too.

We totally understand how you are concerned with the safety of BIGBANG in Japan. Whether BIGBANG can process their concerts safely depends on the places they perform and we will make a decision based on how the Japanese feel and after understanding the situation thoroughly.

Your concerns are justified since amidst such an unexpected disaster, the safety of BIGBANG should be put into careful consideration. Although there are still a lot of variables in the Japan situation, and so is the Japan tour of BIGBANG, I really wish to express my sorrow to the fans who have been hurt in the disaster.

Through this concert, we will keep on consulting with the Japanese side to see how we can help to contribute to the relief work.

Translation: happyrichlife @ameblo & Rice @ bigbangupdates
Source: YG Life Blog