Thailand will spend more than $70 billion on infrastructure over the next five years, Prime Minister Yingluck Shinawatra said as she outlined the challenges facing the country after last year's floods.

In an address to the Foreign Correspondents' Club of Thailand, Yingluck said her government would pursue an economic policy aimed at boosting domestic demand.

It would also 'approve a five-year plan to invest around $72 billion in infrastructure and property enhancing Thailand's long-term competitiveness and to improve the quality of life of Thai people,' she said, pointing to a planned high speed train line from Bangkok to the northern city of Chiang Mai.

Separately, she said the country would invest $11.4 billion in water management measures to ensure there was no repeat of the devastating floods which left more than 800 dead and deluged hundreds of thousands of homes.

Last year's disaster also hit supply chains for Japanese carmakers and Yingluck said steps would be taken to protect investment zones and industrial areas.

The floods were her first test after taking office in August following her party's resounding election victory.

Yingluck said she did not believe the floods or an increase in the minimum wage would scare foreign firms away. The rise from 215 baht to 300 baht ($10) a day takes effect on April 1 in Bangkok and six other wealthier provinces.

She stressed that the minimum wage had not been raised in more than 10 years.

When foreign companies 'invest in Thailand they won't see only the minimum wage packet, they see the long-term (potential) of the country and Thailand is still associated with its strategic location to connect to Asean and other countries in Southeast Asia,' she said.