Thai stocks settled 2.2% higher on Monday, after the country's monarch approved a massive stimulus package to cushion the impact of the coronavirus on the economy, while most other markets in the Southeast Asian region slipped.

The Thai index closed at its highest level since March 10, after the King Maha Vajiralongkorn, over the weekend, approved laws to implement spending measures worth 1.9 trillion baht ($58.55 billion), which allows the government to borrow 1 trillion baht to be used for public health spending and job creation.

Otherwise, a general cautious tone echoed through the region as investors stepped into a busy US corporate earnings week, which is set to reveal the degree of damage COVID-19 has inflicted on businesses.

The United States, which has by far the world's largest number of confirmed coronavirus cases, with more than 750,000 infections and over 40,500 deaths, kicked off earnings season last week with the Wall Street banks.

"The significant amount of uncertainties and the lack of comparative incidents to assess the Covid-19 impact limits the visibility with earnings," Jingyi Pan, market strategist at financial services firm IG, said in a note.

In Asian markets, "caution can likewise be seen setting in awaiting the series of US earnings updates," Pan added.

Indonesia's benchmark index led declines in the region, closing 1.3% lower after data on Monday showed that

incoming foreign direct investment (FDI) in the first quarter shrank 9.2% from a year earlier, as investors delayed business decisions due to the pandemic.

Wires and cables maker Kabelindo Murni and construction services provider Surya Semesta each closed about 7% down.

Philippine stocks settled about 1% weaker, weighed down by financials and telecom sectors.

Globe Telecom fell 2.2%, while BDO Unibank ended 2.4% lower.

Singapore's Straits Times Index finished 0.6% lower, dragged by industrial stocks.

Jardine Matheson Holdings tumbled 4.1%, and Venture Corp closed the session 1.3% lower.