The Senate will remain independent and continue with its mandate in ensuring proper use of public funds, even as the executive department would refuse to cooperate in its proceedings.

Senate President Vicente Sotto III made the vow Tuesday, September 14, after President Duterte told members of his Cabinet that he must authorize their attendance in the upper chamber's legislative hearings.

“That is the prerogative of the Chief Executive. It's up to him. However, the Senate will exercise our legislative oversight function over government projects and expenditures that we approved," Sotto said in a message to reporters.

Sotto also seemed unfazed should Duterte indeed bar key officials and resource persons from attending their hearings.

"That will not be our problem if our legislation will not be suitable to what the executive department’s perspective is," Sotto told the Manila Bulletin in separte message.

He also said: "The independence of the Senate does not rely on the cooperation or the non-cooperation by the exec dept."

"It relies on the resolve of the senators led by the ," Sotto added.

Duterte has launched his crusade against senators for investigating alleged anomalies in the Department of Health's (DOH) disbursement of COVID-19 funds, which the Commission of Audit (COA) flagged for "various deficiencies".

In the course of their probe, senators found out the government's contractors included a newly-registered foreign firm that supposedly lacked the financial capabililty to take on over P8 billion in contracts for pandemic-related supplies.

The firm, they learned, sought the aid of Duterte's former economic adviser, Michael Yang.

Despite Duterte's tirades, senators maintained that they have the responsibility and the authority to ensure that government resources are spent properly.