Jan 12 (Reuters) - Australian buy now, pay later firm Afterpay Ltd (APT.AX) said on Wednesday its $29 billion buyout by payments firm Block Inc (SQ.N), previously known as Square Inc, has received approval from the Bank of Spain, making the deal fully unconditional. With this approval, the companies can now implement the deal, which would be Block"s biggest to date and the largest buyout ever of an Australian firm. Afterpay said the deal is likely to close on Feb. 1. Its shareholders had in December overwhelmingly voted in support of the deal - 99.79% of the proxy votes were cast in favor. Block investors had approved the deal in early November. read more Trading in Afterpay shares will be suspended on the Australian stock exchange on Jan. 19, the company said in a statement.