Before going ahead with the water diversion project across the Mhadei river, Karnataka will need to get the necessary permissions from the central government after completion of a detailed project report, the Supreme Court clarified on Monday.

The Apex court however, did not specifically restrain the Southern state from seeking necessary permissions required for the project, which the Goa government had prayed for in its appeal filed last month.

The appeal had sought directions from the top court to restrain Karnakata from seeking permissions required to construct the Kalasa-Banduri water project across the Mhadei river in order to divert the flow to the water deficit basin of the Malaprabha river.

The Opposition in Goa has called the development a "blow to Goa" in its ongoing inter-state dispute with Karnataka over the waters of the Mhadei river.

Soon after the hearing in the top court Chief Minister Pramod Sawant in a media statement had said that the Supreme Court had said that "no work can be started by Karnataka in implementation of the award without all permissions from central government and without preparing DPR".

In his response Leader of Opposition Digambar Kamat has said that the BJP-led government, the Karnataka government and the Centre had connived against Goa -- a politically less significant state which returns only two MPs to the Lok Sabha -- and Karnataka would soon get the required permissions to start the diversion project.

"The Central Government has already granted permissions to Karnataka and it will take hardly any time for them to prepare DPR and get it approved as the Central Government is in connivance with Karnataka," Kamat told reporters here.

"The Goa Government needs to explain now why they did not object to notification of the Mhadei Award. The opportunity was lost on that day itself when the notification mentioned that Goa had no objection for notification of the award," Kamat said, referring to Goa's counsel not opposing his Karnataka counterpart's request to the apex court last week seeking notification of the Mhadei Water Dispute Tribunal award.

"We had raised strong objections to the permissions granted by the Union Ministry of Environment, Forest and Climate Change to Karnataka for the Kalasa Banduri Project and had also objected to the action of the Ministry of Water Resources notifying the Mhadei Water Dispute Tribunal Award," Kamat said.

"Unfortunately the state government tried to ridicule our concerns and downplayed the serious apprehensions raised by us. Today, the Supreme Court has in a way endorsed our fears about Karnataka starting the work on diversion of water from Mhadei," the former Chief Minister added.

The war of words between Sawant and the Opposition heated up last week, after the Supreme Court allowed notification of the Mhadei Water Dispute Tribunal award given in 2018, on a request made by the Karnataka government.

While Karnataka had claimed that the apex court's nod for notification of the award was a major victory towards its efforts to divert water from the Mhadei river through its controversial Kalasa-Banduri dam project, the Goa government, as well as the state BJP on the other hand has insisted that the nod is merely technical in nature.

The Opposition in Goa has jointly alleged that the state government "did not even oppose" the Karnataka counsel's plea for notification of the award and has demanded a white paper from Sawant, outlining the action taken by his government to safeguard Goa's interest in the ongoing dispute.

Sawant on Wednesday had rejected the Opposition's demand for a white paper, saying his government was doing everything possible to ensure that Goa came up trumps in the inter-state water battle.