Crews battling to avoid a wider nuclear disaster at the Fukushima No.1 plant, which was rocked by the March 11 quake and tsunami, have suffered several setbacks, with workers forced to evacuate by soaring radiation levels.
Tokyo slipped 0.60 percent, or 57.60 points, to close at 9,478.53 and Sydney shed 0.19 percent, or 9.0 points, to 4,733.6, while Hong Kong fell 0.39 percent, or 90.48 points, to 23,068.19.
However, late buying helped Seoul to end up 0.11 percent, or 2.35 points, at 2,056.39, while Shanghai closed up 0.21 percent, or 6.19 points, at 2,056.39.
Investors were upbeat last week as work to contain the Fukushima crisis appeared to be going well, but reports of rising levels of radiation have hampered workers' efforts, stoking uncertainty over how quickly the situation will be resolved.
Dangerous levels of radiation detected in water puddles thought to be leaking from a stricken reactor have also dealt a blow to efforts to restore cooling systems at the plant.
And at a press conference Monday, officials for the first time mentioned the possibility that the core pressure vessels of reactors one, two and three may all be damaged, Jiji Press news agency reported.
Shares in Tokyo Electric Power Co (TEPCO), which operates the plant, plunged 17.73 percent amid criticism over its handling of the deepening crisis.
"The power plant issue is a psychological weight on the market and investors are having a difficult time finding direction amid uncertainty over corporate earnings," said Naoki Fujiwara, fund manager at Shinkin Asset Management.
Concerns over the Japanese crisis overshadowed another strong cue from Wall Street on Friday, where the Dow closed up 0.41 percent thanks to an upward revision of the growth figure for the US economy in the last quarter of 2010.
The Commerce Department said the world's biggest economy expanded at a rate of 3.1 percent in the three months to December 31, up from the initial forecast of 2.8 percent, adding to evidence the recovery there is gaining strength.
The data and comments by Federal Reserve Bank of Philadelphia President Charles Plosser on Friday that monetary policy would have to be normalised "in the not-too-distant future" boosted the dollar.
The Fed in 2008 slashed rates to near-zero in a bid to lessen the impact of the global financial crisis and has flooded markets with cash as part of its quantitative easing policy.
A hike in rates and less money being sunk into the market leads to more demand for the unit.
In early European trade the dollar rose to 81.72 yen from 81.34 late in New York Friday amid hopes interest rates could rise at some point, while the euro slipped to $1.4072 from $1.4088.
Higher interest rates usually support a currency as they make it a more attractive investment proposition.
The European currency traded at 115.02 yen from 114.75 yen.
However, the upbeat data out of the United States sent the Australian dollar to a record $1.0310, its highest since floating on 1983, as dealers developed more risk appetite.
On oil markets, crude eased slightly but uprisings across the oil-rich Middle East and military strikes on crude exporter Libya supported prices.
New York's main contract, light sweet crude for delivery in May, dipped 38 cents to $105.02 per barrel while Brent North Sea crude for May lost 14 cents to $115.45.
Gold closed at $1,418.00-$1,419.00 an ounce in Hong Kong, down from Friday's close of $1,433.00-$1,434.00.
In other markets:
-- Singapore fell 0.44 percent, or 13.46 points, to 3,057.38.
DBS Bank gained 0.14 percent to Sg$14.34 while Singapore Airlines fell 0.45 percent to Sg$13.40.
-- Taipei fell 0.67 percent, or 57.33 points, to 8,553.06.
Taiwan Semiconductor Manufacturing Co was 0.28 percent lower at Tw$71.0 while MediaTek lost 0.73 percent at Tw$340.5.
-- Manila rose 0.98 percent, or 38.17 points, to end at 3,913.98.
Energy Development gained 0.8 percent to 6.00 pesos and Philippine Long Distance Telephone added 0.6 percent to 2,036.
-- Wellington ended 0.57 percent, or 19.44 points, higher at 3,408.05.
Fletcher Building, which will lead reconstruction efforts in Christchurch after the recent deadly earthquake, rose 2.3 percent to NZ$9.24, while Air New Zealand ended 0.9 percent higher at NZ$1.10.
-- Jakarta fell 0.12 percent, or 4.25 points, to 3,602.86.
-- Kuala Lumpur ended flat, edging down 1.30 points to 1,514.25.
UEM Land fell 3.3 percent to 2.67 ringgit, Tenaga Nasional shed 1.5 percent to 6.00 and Petronas Chemicals closed up 1.8 percent at 6.95.
-- Bangkok fell 0.46 percent, or 4.79 points, to close at 1,032.94.
Banpu lost 10.00 baht at 756.00 baht and PTT fell 2.00 baht at 346.00.
-- Indian shares rose 0.68 percent with the benchmark 30-share Sensex Index ending up 127.5 points to 18,943.14.
Tata Motors rose 3.25 percent or 38.45 rupees to 1,220.3, Bharti Airtel rose 2.57 percent or 8.7 rupees to 347.8 while DB Realty plunged 14.02 percent.