The bonds, part of a plan to issue up to 50 billion baht over the next three years, would help manage funding costs, investment banking chief Tanate Phutrakul told reporters.
"We plan to do it this year but are looking for the right time. The market is quite volatile now as interest rates are rising," he said without elaborating.
The Bank of Thailand has raised rates 8 times since August 2004 to fight surging inflation.
Bank President Subhak Siwaraka said TMB expected better profits in 2006 as it aimed to lend 40-50 billion baht, or 8 percent more, after 6-8 percent growth expected for this year.
It would focus still on lending to retail businesses and the government's $44 billion of 5-year infrastructure projects, Subhak said. The state-run bank is expected to make a net profit of 7.55 billion baht this year and 7.7 billion baht in 2006, according to a mean forecast by 9 analysts surveyed by Reuters Estimates.
Its 9-month net profit rose 48 percent to 6.2 billion baht.
TMB, formerly Thai Military Bank, planned to spend 1.4 billion baht over the next 18 months on branch upgrades and rebranding, Subhak said.
TMB, which took over two financial institutions in 2004, aimed to boost fee income to 25 percent of revenues from 20 percent now, he said.
TMB shares were down 0.5 percent at 4.18 baht at 0831 GMT, while the overall Thai stock market was 1 percent lower.