By Scott Murdoch and Yantoultra Ngui

SYDNEY (Reuters) -At least two Asia Pacific banks, led by Commonwealth Bank and DBS Group (OTC:), have aggressively tapped U.S dollar bond markets to raise $4.75 billion in separate transactions, according to term sheets seen by Reuters.

CBA, which is Australia's largest bank by market capitalisation, raised $3.25 billion in three issuances with $1.75 billion in a five-year covered bond, $900 million in a two-year fixed rate note and $600 million in a two-year floating rate note, a term sheet showed.

CBA declined to comment on the transaction.

Singapore's biggest bank DBS Group tapped the dollar bond markets for the first time in nearly two years as it raised $1.5 billion.

The deals came amid a blitz of bonds launched on Tuesday in the US when there were 21 issuances worth $31 billion, according to IFR.

A post Labor-day rush of bond issuance in the U.S. by global investment-grade-rated companies added renewed pressure on long-end U.S. Treasuries, as some investors switched to buying top-rated corporate debt offering higher yields than those on government bonds.

DBS, which is also Southeast Asia's largest lender, issued a two-year fixed rate bond that raised $750 million and a two-year floating rate note that raised the same amount, the term sheet said.

The coupon on the fixed rate note was set at 5.479% while the floating rate note was priced at the Secured Overnight Financing Rate (SOFR) plus 61 basis points.

Investors subscribed for more than $2.65 billion of the two- year fixed rate bond, the term sheet showed. The floating rate note attracted over $2 billion in orders from investors.

"The strong momentum of the order book, which was three times oversubscribed, is testament of the market's confidence in DBS," said Chng Sok Hui, Chief Financial Officer of DBS Bank.

U.S. and Asia-based investors bought nearly 90% of the fixed bond and accounted for 98% of the floating note, the term sheet showed.

DBS has flagged that the proceeds from the bonds would be used for its finance and treasury activities.