By Yantoultra Ngui

SINGAPORE (Reuters) -Singapore will block a bid by German insurer Allianz to buy a majority stake in Singapore's Income Insurance but remains open to a new deal if its concerns can be addressed, Prime Minister Lawrence Wong said in a Facebook post on Monday.

Allianz proposed the deal valued at S$2.2 billion ($1.68 billion) in July as part of its strategy to strengthen its foothold in Asia, which would make it Asia's fourth-largest insurer, up from ninth previously.

The transaction faced backlash in the city-state as Singaporeans worried that the deal would detract from a mission to provide affordable insurance for lower income workers.

Wong said on Facebook the government, while reviewing the proposed sale, came across additional information that gave it "cause for concern" but did not elaborate."The Government has therefore decided not to approve the transaction," he wrote, but noted there were no concerns over Allianz's suitability to acquire a majority stake in Income.

"We remain open to a new deal that Income may pursue with Allianz or other partners, so long as our concerns are fully addressed," wrote Wong.

Allianz responded on Monday that the deal would benefit Singapore's customers and society and that it would consider revisions to the proposed transaction structure.

Top shareholder NTUC said it would study the implications of the government's position and work with stakeholders on how to proceed.

Income Insurance did not respond to requests seeking comment.

($1 = 1.3061 Singapore dollars)

(Reporting by Yantoultra Ngui, additional reporting by Xinghui Kok in Singapore and Tom Sims in Frankfurt; Editing by Kim Coghill, John Mair and Richard Chang)