Metro Manila (CNN Philippines) — Senator Richard Gordon issued strong words for some senators whom he accused of pretending to support the administration.

Gordon was referring to senators Franklin Drilon, Leila De Lima, Bam Aquino, Francis Pangilinan, and Risa Hontiveros, who all belong to the Senate majority bloc.

"It seems we have an opposition in the Senate masquerading as part of the administration," Gordon told CNN Philippines' The Source. "They have to take their mask out."

When asked if they should leave the majority bloc, Gordon replied, "I think so. I think they should do that."

Gordon criticized the five senators for "acting in unison" with two minority senators, Antonio Trillanes IV and Ralph Recto.

Gordon said the seven senators have already been "acting in unison in all issues," and "most of the issues, or all of these, are practically against the administration."

"I think if you are in the opposition, you should stay in the opposition," said Gordon.

He added that many senators agreed with him.

Members who leave the majority stand to lose their chairmanships in certain senate committees.

Immigration scandal probe

Gordon's beef against his five colleagues stems from an earlier resolution filed by Drilon. Drilon's Resolution 256 asked the committee headed by Trillanes to lead the investigation into an extortion allegation against two former officials of the immigration bureau, Al Argosino and Michael Robles.

Trillanes heads the Senate Committee on Civil Service, Government Reorganization, and Professional Conduct. In his resolution, Drilon argued that Trillanes' committee should lead the probe because a reorganization is needed in the Bureau of Immigration (BI).

However, instead of voting on whether to approve Drilon's resolution or not, the Senate instead put out a vote to refer the matter to the Senate Committee on Rules, headed by Majority Leader Vicente Sotto III.

In a 14-7 vote last Monday, majority of senators voted to refer the issue to the senate rules committee. With that vote, Sotto's committee has been tasked to determine which senate committee should lead the investigation into the immigration scandal. This effectively stripped Trillanes of the opportunity to conduct the investigation.

The seven senators on the losing side of the vote were Drilon, Trillanes, Ralph Recto, Leila De Lima, Bam Aquino, Risa Hontiveros, and Kiko Pangilinan.

As the matter stands, the senate investigation is still pending, until Sotto's committee recommends what it deems to be the proper committee to lead the probe.

Plenary tussle

During Tuesday's plenary session, Sen. Miguel Zubiri suggested referring the investigation to the Committee on Justice, headed by Gordon.

Gordon agreed, adding that the investigation can also be referred to the Blue Ribbon Committee, which he also chairs. The Blue Ribbon Committee focuses on issues surrounding the accountability of public officers.

"The substance of the (Drilon) proposal ostensibly says reorganization," Gordon explained. "But because of the recent corruption involved in the bribery of two commissioners... that is really justice, more apropos to the Blue Ribbon Committee."

Trillanes, a former Navy officer, then stood up and accused Gordon and Zubiri of attempting to "whitewash" the investigation. This escalated into a near-fistfight between Trillanes and Zubiri.

Related: Trillanes, Zubiri almost come to blows after tussle over immigration scandal

Drilon responds

In a phone call with CNN Philippines' Balitaan, Drilon explained affiliation with the administration was not a consideration of the majority bloc.

Rather, he said they constituted the majority because they voted for Sen. Koko Pimentel as the Senate President.

"We are not masquerading as a majority. We were in the majority, and we are in the majority, because of our support for the Senate President," said Drilon. "That the Senate President is now affiliated with the administration is a fact that came afterwards."

He added that the Liberal Party had cast its vote in favor of Pimentel, and the majority was formed on the basis of this support.

"We did not talk about the administration. We just said Pimentel is our [Senate] President in so far as the party is concerned," Drilon added.

As such, Drilon said that they will stay in the majority bloc.

Drilon also reiterated the nature of his resolution asked for a review of restructuring the BI, which is why he recommended it to Trillanes' committee.

He added that such disagreements are normal in the Senate.

Gordon urges ethics complaint vs. Trillanes

Gordon also slammed Trillanes for "unethical conduct" in his behavior at the Senate yesterday.

"When you become a Senator, it is a place of honor, it is a position of honor. You use your mind, you use your talent, your skills and your research to be able to argue out," Gordon said.

He even urged that a complaint should be filed against him at the Committee on Ethics, noting that anybody could file an ethics complaint.

"Unethical conduct — that should have been referred to the Committee on Rules, on the Committee on Ethics right away," said Gordon.

Gordon could not say that who would file the complaint, but he anticipates that one will come up.

"You cannot be using the same bullets over and over again," he said. "At some point in time, there will be a reckoning."