MANILA -- Candidates running for the Senate next year might face the prospect of a 6-year term cut short with the shift to a federal system of government, the head of a Malacañang body drafting a new federal charter said Thursday.

Former Chief Justice Reynato Puno bared the proposed constitution’s transitory provisions, which sets the first elections under the federalism in May 2022.

If adopted by the planned constituent assembly, the proposal would mean winners in next year’s senatorial election would serve for only 3 years, he said.

"All the terms would end by 2022," he told reporters on the sidelines of a forum in Manila. "They would have to take that chance."

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Puno's committee is putting the finishing touches on a proposed constitution that includes a shift to a federal system of government and key political and electoral reforms.

But the proposal is dependent on the approval of Congress, and later, by the public in a plebiscite.

Puno said the plebiscite should be held "ideally" before next year’s elections. One concom member earlier said it could also be held simultaneously with the mid-term polls.

"Hindi natin alam. Hindi nga natin alam kung maaaprubahan ng Kongreso," Puno said.

(We don't know. We don't even know if Congress will approve it.)