Video showed Mrs Merkel, 64, gripping her arms as her body was shaking on Thursday. After about two minutes, she looked steadier and shook hands with the new justice minister.
She was offered a glass of water, but did not drink it.
Mrs Merkel had blamed the previous incident on dehydration, BBC reports.
Her spokesman said she would set off for Japan as planned at lunchtime.
"All is going ahead as planned. The federal chancellor is fine," spokesman Steffen Seibert said.