Panama’s largest construction workers’ union on Monday renewed its threat to call a national strike as part of protests to raise safety conditions on building sites, boost the minimum wage and lower basic food prices.

The threat, made by Genaro López, secretary-general of the Suntracs builders’ union, comes in spite of a presidential decree on Saturday that aims to address workers’ demands for more rigorous safety standards on most of Panama’s building sites.

But in an interview on Monday with the Financial Times, Mr López hinted strongly that the decree might not be enough: “This protest goes far beyond labour safety conditions.”

He said his union had called a meeting this Saturday to decide its action.

Some experts fear that a long protest by Suntracs’ 50,000 members could disrupt a dynamic sector of Latin America’s best­ performing economy.

Last year, the country grew 10 per cent, according to official figures released this week, about 30 per cent more than initial government estimates made at the end of 2006.

Much of that growth was thanks to a construction boom that is transforming the Panama City skyline.

According to Samuel Lewis, Panama’s vice-president, direct foreign investment was expected to have reached $2.5bn by the end of last year.

Mr López’s comments follow a week of protest as construction workers took to the streets at the beginning of last week. On Wednesday, about 200 union members were detained and arrested after Iromi Smith, a colleague, was shot dead.

Residents of Panama City and Colón on the country’s Atlantic coast, waited in anticipation on Monday of further clashes between police and protesters at Mr Smith’s funeral, on Tuesday in the city of Cólon.